Hey, Electric Rain. Sorry I got cut off from AIM yesterday (campus lab shut down at 2am). Anyway, I couldn't find that link you wanted on the other game controllers (N64, DC, Genesis, etc) but basically, I found it the first time just using Google over and over again.
The PSX, SNES, and NES signals seem to have the most in common. N64 is a bit differenent because it uses a discreet PWM instead of basic highs & lows. Gamecube might be a problem, because it seems to run on 3.4v logic and the I/Os aren't TTL tolerant. The other ones I haven't researched much but they're generally better-documented than the PS2 type I was looking for.
Well, 'hope all this helps.