This reminded me of rumors I'd heard about just such a pre-Boo arc Super Saiyan guide that was supposedly featured in the anime comics version of the Trunks TV special. As it turns out, Mike owns that book and was willing to break its spine to accommodate me, so now we've got great scans of this feature. This book was published on May 31st, 1993. At this point in time the manga was just beginning the Boo arc, while the anime had only just recently passed the point where Gohan transforms into (what would later be known as) Super Saiyan 2. Specifically, Gohan transforms in DBZ episode 184, broadcast May 5th 1993, while the last episode shown in May was 187, where Cell reverts to his second form. As a result, while this feature is anime-based and therefore illustrated with anime screan-shots, they pretty much had to fake it with Super Saiyan 2 Gohan. There's a very nice original drawing of him in this form, and a screan-shot of...regular Super Saiyan Gohan, from near the start of his fight with Cell.
Anyway, what the heck did they call Super Saiyan 2 Gohan if the term "Super Saiyan 2" wouldn't debut in the manga for over a year (in chapter 474, published June 1994)? Well, you may be familiar with the "Grade" terminology used to refer to the very muscular Super Saiyan forms used by Vegeta, Trunks, and (very briefly) Goku. Often called "Ultra Super Saiyans" or "Ascended Super Saiyans" by fans, Daizenshuu 2 labels these forms "Grade Two" and "Grade Three". "Grade Two" refers to the muscular form in which Vegeta dubs himself "Super Vegeta", while "Grade Three" is the even more muscular form Trunks uses to fight Cell, the one which proves uselessly slow. This terminology derives from chapter 387, where Goku shows off Super Vegeta's style of transformation to Gohan, then says that "one further grade of transformation is possible", at which point he transforms into Trunks' ultra-muscular but slow form. "Grade" in this case is 段階/dankai, which can also be translated as level, tier, stage, and so on; Viz uses "notch" in their translation of Goku's line. So if Goku goes up "a further grade" to reach Trunks' form, then by extension Super Vegeta's form must be a grade up from regular Super Saiyan. Going by that, you can label regular Super Saiyan as "Super Saiyan Grade One", Super Vegeta's form as "Super Saiyan Grade Two", and Trunks' crazily muscular form as "Super Saiyan Grade Three", which is precisely what the Trunks anime comic feature does, and what later things like Daizenshuu 2, the GT Perfect Files, and the recent video games use to refer to the muscular forms (it's comparatively rare for anyone to actually bother referring to regular Super Saiyan as "Super Saiyan Grade One").
The interesting thing with the Trunks anime comic feature, which distinguishes it from Daizenshuu 2 and the other later sources, is that it extends this "Grade" naming scheme to cover the natural, "at ease" version of Super Saiyan which Goku and Gohan ultimately adopt (what Daizenshuu 2 calls "Full Power Super Saiyan" and fans often call "Mastered Super Saiyan"), as well as Gohan's transformed state at the Cell Games (what we now of course know as Super Saiyan 2). So, they label the at-ease Super Saiyan as "Super Saiyan Grade Four", and Gohan's form as "Super Saiyan Grade Five".
Yes, an official publication kinda-sorta labeled something Super Saiyan 5...come to think of it, if we extend this naming scheme even further, then Super Saiyan 3 becomes "Grade Six" and Super Saiyan 4 is "Grade Seven", a perhaps appropriate number for what actually ended up being Dragon Ball's final Super Saiyan form. On that note, the entry on "Super Saiyan Grade Five" also labels it the "Strongest Form" (compared with Grade One, the "Basic Form"), which of course it was at the time, though this was not to last long.
So there you have it: "Super Saiyan Grade Five" was, as far as I know, the earliest official name given to what is now universally called "Super Saiyan 2". In the series they do toss around phrases like "a Super Saiyan surpassing Super Saiyan", but these aren't really names (though they are probably what led the Funi dub to use the term "ascended Super Saiyan" for it and other forms). Obviously, once Goku gave it an actual name within the series itself that's what ended up sticking. Though as Blade points out in the other thread, the phrase "Super Saiyan 2" is only ever used that one time when Goku explains about Super Saiyan 3 to Babidi and Boo, and Goku's explanation makes it clear that these "Super Saiyan 2/3" names are things he came up with for convenience's sake ("a Super Saiyan that has surpassed Super Saiyan...'Super Saiyan 2', you could call it"). The reason we're all so familiar with this term is mostly due to secondary sources like the guidebooks, video games, toys, etc. From an in-universe perspective, it's not really written in the stars that "Super Saiyan 2" is the name of this form. They do toss around "Super Saiyan 3" a fair deal, a name which of course is based on Gohan's Cell Games form being called "Super Saiyan 2", but as noted this is likewise just Goku's personal terminology, later adopted by others. When Trunks and Goten stumble upon the Super Saiyan 3 form as Gotenks, they label it "Ultra Super Saiyan". Not that I want people to stop using the terms "Super Saiyan 2/3", but it's good to remember precisely how they originated.
As mentioned, Daizenshuu 2 uses the "Grade" terminology to refer to the muscular forms. This comes in the book's "Growing Up" section, which goes over the different ages, appearances, and forms of the characters throughout the series. Before I had thought this is where the "Grade" terminology originated, but it now seems it was first used in this Trunks anime comic feature, unless some even earlier source pops up. However, while it uses "Grade Two/Three", Daizenshuu 2 uses "Full Power Super Saiyan" rather than "Grade Four" (and only in reference to Goku; Gohan is simply labeled "Super Saiyan"), and "Super Saiyan 2" instead of "Grade Five". They don't even mention "Grade Four/Five" as alternate names. This is perhaps not surprising for Super Saiyan 2, but the natural/at-ease version of Super Saiyan never got any name in the series, so it's interesting that they opted to coin the phrase "Full Power Super Saiyan" rather than reuse "Grade Four". Incidentally, "Full Power Super Saiyan" seems to derive from the title of chapter 398, "Full Power Son Goku"; the chapter (predictably) features Goku beginning to fight Cell at full power, hence the title.
So while the term "Super Saiyan 2" didn't exist when the Trunks anime comic came out, and was never even a set-in-stone name from an in-universe perspective, we might ask how much sense it ever made to include it and the natural/at-ease Super Saiyan under the "Grade" umbrella. With the muscular forms it's pretty straight-forward: Goku becomes a regular Super Saiyan, from there transforms into a muscular form, says a "further grade of transformation is possible", at which point he transforms into the even more muscular form. This sequence of events seems to directly establish the first muscular form as a "grade of transformation" higher than regular Super Saiyan, and the even more muscular one as a still higher grade, hence "Grade Two" and "Grade Three". The terms comes right from what's said in the series. But nothing Goku or anyone else says establishes the at-ease Super Saiyan as a further grade of transformation from the muscular forms, or even as a transformation distinct from ordinary Super Saiyan at all (but that's another discussion). Super Saiyan 2 certainly seems like a further transformation from the at-ease Super Saiyan, but nothing really connects it to the muscular forms; certainly Gohan didn't need to reach the muscular forms before reaching Super Saiyan 2 (as far as we know). I'm not saying that the Trunks anime comic feature was wrong to apply the "Grade" terminology to these two forms, but I do think it was an inherently shakier proposition than using the "Grade" names for the muscular forms. And I think this is probably one reason later sources still keep the "Grade" names for the muscular forms but not for Super Saiyan 2 or the at-ease Super Saiyan.
Now you may be wondering if there's anything else of interest in the Trunks anime comics feature on Super Saiyans. I've actually translated the whole thing and will post it at the end here, but it's mostly just stuff you already know. Still, there are a couple of interesting bits. Like Broli! The feature wraps up with a brief look at Broli's Super Saiyan forms, saying he's a Super Saiyan who has achieved a different evolution than Goku and co. This "different evolution" phrase is also used to describe Broli in the Super Saiyan chart featured in the supplemental daizenshuu TV Animation Part 3, which may have been using this earlier Super Saiyan guide as a source. The Trunks anime comic one labels Broli's weird blue-haired Super Saiyan form as simply "Super Saiyan", and his super muscular form (what's commonly called his "Legendary Super Saiyan" form) as "Super Saiyan (Final Form)". It notes that his Final Form resembles Super Saiyan Grade Three, but that its speed is "ultra first-class"; it's here they throw in how he's achieved a different evolution than Goku and co., implying that this is why he has a form that is similar to Grade Three but without its weaknesses. Since the Trunks anime comic predates all but the very beginning of the Boo arc, it likewise predates the follow-up Broli movies, and so doesn't mention Broli's more ordinary golden-haired Super Saiyan form from DBZ movie 10, or Bio-Broli.
The explanation for regular Super Saiyan says that in this form a Saiyan's battle power is "dramatically" higher; it seems the x50 multiplier had yet to debut. Interestingly, "battle power" and "the height of their ki" are listed as separate things, along with their "muscle strength". An explanation on the legend of the Super Saiyan says that in the legend they are called the "ultimate evil", something I don't think is mentioned anywhere else.
The explanation for Grade Two says it increases speed as well as power. Daizenshuu 7 and the GT Perfect Files say the same thing, which is interesting in light of how Grade Three ends up lowering speed. Apparently the muscle increase that goes along with this transformation is not enough to lower speed like in Grade Three, or perhaps the increase in ki (which should increase speed, based on Vegeta's comment to Kewi about higher battle power meaning greater speed) is enough to cancel out the slowing effect of the increased muscles.
The explanation for Grade Three says that "it seems that Vegeta is also capable of transforming into a Grade Three". In the series, Trunks says that Vegeta must have realized the form's weaknesses and that this is why he never performed the transformation, which does imply he was capable of doing it.
Though the guide is mostly illustrated with anime screenshots, for some reason the explanation of how Cell could perform the Grade Three power up features a strange-looking colored version of Cell from the manga showing off this transformation to Trunks.
An explanation of the Room of Spirit and Time says that time flows slowly there, and that a year outside the room is equivalent to a year inside. Oops. They elsewhere refer to Gohan training a year inside the room, so apparently they were just careless when writing that passage.
And that's about it. Here's the whole thing, which runs from page 142 to 147 of the book. Big thanks to Mike for scanning it for me. Now is as good a time as any to note that I ordinarily use Roman numerals when referring to the Grade forms (ie "Grade II", "Grade III"), though for this thread and this translation I've instead just written the numbers out (ie "Grade Two", "Grade Three"), because...just because. Both of these writing schemes are simply my attempt to help visually distinguish the names of the Grade forms from "Super Saiyan 2/3/4". With the Grade forms, they use Japanese numbers (ie, the kanji for the numbers along with the regular Japanese reading), while with Super Saiyan 2/3/4 they use the English numbers (or rather, they use the Arabic numerals with furigana indicating they should be read as the English words for those numbers). This distinction is of course hard to maintain when translating into English, but I figured that avoiding using Arabic numbers when referring to the Grade forms was as good a way as any. Anyway, here we go:
The Theory of Super Saiyan Evolution
The 4 Super Saiyans power up each time they battle a strong foe! This complete analysis categorizes the process and history of their evolution, grade by grade!
Super Saiyan Grade One (Basic Form)
When they transform into Super Saiyans their battle power, the height of their ki, and muscle strength are all dramatically increased compared to when they are regular Saiyans! What's more, once they transform their black hair stands straight up and is dyed gold, and they emit an intense aura. This form could be called the basis for all later Super Saiyans from Grade Two onward!![purple box]
What is a Super Saiyan!?
"Super Saiyan" refers to a legendary Saiyan warrior said to appear once in a thousand years. In the legend, a Super Saiyan was called the ultimate evil, loving blood and battle. It is the strongest super warrior in the universe, who has overcome the limits which no warrior no matter how gifted could overcome!
On Planet Namek Goku challenged Freeza (in his third transformation form) to an intense battle, and when Kuririn was killed his anger transformed him into a Super Saiyan! Afterwards, he adopted the pattern of normally living as an ordinary Saiyan, and transforming into this Grade One during battle.
[red text] Strongest in the galaxy! The miracle-working super warrior!!
[picture of SSj Goku, I think from before he fights No.19] When he transforms into a Super Saiyan, even his personality becomes wild. This is because he is in a continuous agitated state, increasing his ferocity.
[picture of SSj Goku fighting Freeza] Super Saiyan Goku even won a magnificent victory against full power Freeza!!
[picture of regular Goku using Teleportation] He can use techniques such as Teleporation and the Kamehameha even as a Super Saiyan!
Son Gohan is a kind-hearted boy who loves peace and hates fighting. But the blood of the Saiyans, the strongest fighting race in the universe, flows inside him! Gohan finally transforms into a Super Saiyan after receiving special training directly from Goku in the Room of Spirit and Time! The power that was hidden inside of him is greater than Goku's!?
[red text] Unleash dormant power!!
[Gohan's regular and Super Saiyan forms]
After transforming, the look in his eyes is different than before; his pupils and hair color change as well. He has a Goku-esque vibe; like father, like son!
When Vegeta learned that Goku had transformed into a Super Saiyan, he began intense training as he traveled the universe on his own! Through his anger towards Goku and himself (for being unable to surpass Goku), he transformed into a Super Saiyan, capable of using a great technique called the Big Bang Attack!
[red text] The Saiyan prince who aims to be the best in the universe!!
[regular Vegeta in front of the Room of Spirit and Time door] Vegeta transforms into a Super Saiyan through his calm heart of pure evil!
The future was devastated by the androids' assault. While still a boy, Trunks transformed into a Super Saiyan through his anger at the death of his mentor Gohan, who was killed by No.17 and No.18! When he came to the past, he already had enough power to defeat Freeza and his father in one blow as a Grade One!
[red text] The Super Saiyan warrior from the future!!
[Super Saiyan Trunks] Trunks is an Earthling/Saiyan hybrid. Because of this, his hair is not black (a distinguishing feature of the Saiyans)
Super Saiyan Grade Two
A Super Saiyan that has surpassed the limits of Super Saiyan: that's Grade Two! Muscles are even larger than in Grade One, with power and speed raised as well! The shape of the Super Saiyan's trademark upright hair is also even more combative. When Vegeta underwent this transformation during his battle with second stage Cell, he called himself "Super Vegeta".
Vegeta underwent ultra special training in the Room of Spirit and Time. The fruits of his labor were this Grade Two transformation and the great Final Flash technique, which has enough force to shatter the Earth! Though he's a warrior who surpasses even stage two Cell, his power was no match for Cell in his perfect form.
[red text] A Super Saiyan that has surpassed its limits!
[Super Vegeta punching second form Cell] Speed and power that overwhelms second stage Cell! Cell couldn't even lay a hand on Super Vegeta!
Trunks became capable of transforming into Grade Two through his training in the Room of Spirit and Time, which he entered with Vegeta. He first showed off this transformation when trying to stop Cell from absorbing No.18!
[Trunks blasting Vegeta] Trunks fires at his father Vegeta, who's helping Cell. He's grown a lot emotionally too!
Goku passed on the secret of the Super Saiyan transformation to Gohan. He demonstrated the Grade Two transformation for Gohan, then continued right on to Grade Three!
Super Saiyan Grade Three
A Super Saiyan with overwhelming power that far surpasses even Grade Two! But the enlarged muscles get in the way and kill speed. In other words, it could be called a transformation that relies too much on power. Another flaw is that its energy consumption is too intense.
In terms of power he even surpasses Super Vegeta (Super Saiyan Grade Two)! After Super Vegeta was defeated, he challenged Cell in his stead, but was outclassed in speed and sadly suffered a complete defeat. Incidentally, it seems that Vegeta is also capable of transforming into a Grade Three.
[red text] Challenging evil with gigantic power!!
[Cell dodges Trunks' punch] His speed is drastically reduced due to his muscles! Attacks are meaningless if they don't hit!
He transforms into a Grade Three during his training in the Room of Spirit and Time! This grand form amazed and impressed Gohan, but Goku spotted its flaws: its intense energy consumption and the way that its muscles lower speed!
[red text] A max power super warrior![purple box]
Cell is also capable of the same transformation!?
Cell was startled when he saw Trunks transform into Grade Three. But the truth is that Cell himself is also capable of this power up! However, he realized that a transformation that relied on power was meaningless. He therefore tried to avoid using it.
Super Saiyan Grade Four
A form where without consciously raising their ki they are still able to remain Super Saiyan on a regular basis: that's Grade Four. From the start Grade One balanced power, energy consumption, etc. This form removes the slightly agitated state which characterizes Grade One. It's a natural form of Super Saiyan which has even gotten rid of their wild personality!
He grew a lot both physically and mentally during his roughly 1 year of training in the Room of Spirit and Time! After Goku surrenders, he succeeds him in stepping up to the Cell Games ring and challenging perfect form Cell! His clothes were given to him by his martial arts master Piccolo.
[red text] The strongest boy warrior!
[Cell bear hugs Gohan] Though possessing power surpassing Cell, his gentle heart shied away from battle!
Goku transformed into Grade Four during his training in the Room of Spirit and Time, and stepped up to the ring as the first challenger in the Cell Games. Though he put up a good fight against perfect form Cell, he sadly resigned, and selected Gohan as Cell's next opponent.
[red text] A Super Saiyan of furious power!![purple box]
Intense training in the Room of Spirit and Time!!
The Room of Spirit and Time is located in God's temple; it completely cuts off all information from the outside world. The gravity, temperature, etc, are all far harsher than in the outside world! The flow of time is also slow, and a year in the outside world is equivalent to a day inside the room [...ugh...no...not quite...]! Goku entered once when he was young.
Super Saiyan Grade Five (Strongest Form)
An aura with sparks like flashes of lightning and an upright, combative hairstyle are the distinguishing features of this, the strongest Saiyan warrior! One's personality also becomes aggressive; even the ordinarily gentle Gohan started to enjoy battle! Its power is enough to push back even Cell's energy bullet, which had enough force to blow away the Solar System!
Gohan's true power that had lain dormant finally awakens! He transforms through his extreme rage towards Cell, who tormented Goku and the others with his Cell Juniors, and even destroyed No.16! His personality does an about-face; the strongest Super Saiyan, he easily battles Cell!
[red text] Everything's super!! Declare this invincible Saiya-Power!!
[picture of SSj Gohan, from right after Cell beats him up and knocks him into the mountain...in other words, not SSj2 Gohan, though they're implying it is] Outraged at the cruelty of Cell and the Cell Juniors, Gohan finally transforms![purple box]
Super Saiyans transform through anger!!
Goku transformed into a Super Saiyan through his anger at Freeza, after Freeza killed Kuririn. Trunks likewise transformed into a Super Saiyan through his anger towards the androids. In other words, anger is what fuels the power of Super Saiyan evolution!
[SSj Vegeta] It's also possible to transform through anger at yourself, like with Vegeta!
[SSj Gohan] You can't awaken into a Super Saiyan unless you are a fighting genius!
[pink box with Broli]
A Super Saiyan that has achieved a different evolution!!
Broli appeared in the movie "Burn Up!! A Red-Hot, Raging, Super Fierce Fight". His final form resembles Super Saiyan Grade Three. But his speed is ultra first-class, and he could be called a Super Saiyan who has achieved a different evolution than Goku and the others!
[lineup of Broli's forms]
--Super Saiyan (Final Form)