How about a GIANT tournament, bigger than the hades cup, with all the big bosses, like proud clod, sin, vegnagun, all the weapons, Seymour, Sinspawn, Necron, Kuja, Hundred Gunner, Materia Keeper and Apps.
Oh and all the characters like Yuffie, Squall (i hate Leon), Cloud, Lulu and Zidane and all.