Bomberman could happen since Hudson is on Good terms with the N
Megaman could happen because Capcom loves money, and isn't so staunch (sp?) a suporter of Sony (or M$ for that matter) that they haven't made games for the wii, or ignore the free advertising that Megs, and a Capcom AT could bring
Cloud and Sora have a possibility on a technicality. It's not big, but it's there
Belmont: see above
Geno: is owned by Square, is from SMRPG, and has made a few cameos in stuff like M&L superstar saga.
Shadow: see above