Tatsu, are you talking about pitting console players against PC players?
I'm not familiar with xpadder but I'm assuming that it allows like a keyboard/mouse input for use on a gaming console? In either case, it just wouldn't be fair to force one type of player to game against the other as the PC keyboard/mouse has a tremendous advantage over the gamepad. I'm not saying it wouldn't be fun, but I am saying that for tournament purposes it would definitely not be a level playing field.
I'm also not saying that PC players are superior to console players, it's just a different type of play...although even if I'd never played a game, like say Halo3, give me 15min to map my keys and learn the map and I could probably take out a very good 1v1 console player that was using a gamepad.
In short, we can't mix and match...because if we did, I would participate and take all your lunch money
-darkdisk