XIII 2: Covert Identity...ok its a sequel to the mobile version. Would love to see a new XIII title.
H.E.R.O. (sadly a sequel never made it as the game didn't sell well due to it coming out about the same time as the videogame crash)
Ristar. (Pisses on Sonic)
Sin & Punishment. (possible seeing Treasure have done Guardian Heroes, Bangai-O & Gunstar Heroes sequels)
Urban Chaos (the PSX/PC/DC one, this one used the Tomb Raider engine but was really good)
Secret of Evermore. (I'm sick of these samey themed RPG's, give me a sequel!)
Beyond Good & Evil. (Might be happening in the future)
Kid Icarus II. (Come on Nintendo!)
Startropics II. (Better than Zelda NES, would be great on the Wii)
Cannon Spike. (Fantastic Smash TV style shooter which starred Mega Man, Cammy from SSF2, Arthur from Ghosts 'n Goblins plus other Capcom characters)
ExciteBike 64. (Best dirt bike racer ever, NitroBike is coming to Wii from the devs so that might be the closest thing we'll ever get)