Scratch that, I'm not quite done with it yet. Here is a list of N64 and SNES games that were popular to some extent but haven't had sequels:
N64
Pilotwings
Blast Corps
Jet Force Gemini
DK Country
SNES
Actraiser
Chrono Trigger
Earthbound
Mario Paint
Punch Out (apparantly ruled out by Matt according the IGN boards)
So add it to my previous NES list and that is pretty much what we are looking at here. How much gamers are demanding each franchise or which would get Matt and Bozon so excited I won't argue. I'll just end with that I think the three main possibilities are
1) Retro making Kid Icarus
2) Factor 5 making Pilotwings
3) Monolith making Earthbound