Well it's pretty big at my school because we're pretty damn good at it, if I may say so myself.
Just off the top of my head, I think we'll need another sprite for the trainer card. That shouldn't be too hard (just loading a different sprite and palette) but you'll have to make one first. Other than that, though, I think it's all ready. By changing the variable to '0x7000', the change will now stay even if the player saves and restarts the game. There's still the problem of the history thing. I think I might know a way to disable the change during the history but the problem is that we want the change to show sometimes and other times not. Bleh, it's too complicated. I'mma go work more on that SMW2 hacking. I've found the level headers (the data which determines which sprites to load, which color Yoshi to use, which background to use, etc.) and I think I might have found the level data also. I just need to figure out how the data in the ROM gets converted into the data which gets written to the WRAM. Anyway, I'll try to log on tomorrow but as always, there's no guarantee.