you could make an adapter for snes to gc controller useage, but it probably would't be worth the time, since it shouldn't work on most games anyway. Most GC games are analog, and all SNES games are digital. Not to mention the SNES pad is missing a Z- button, but does have a select button. Where is is really lacking is the fact that it doesn't have either of the analog stick, which means you wouldn't be able to control you character or the camera.
I would mention the digital click on the shoulder button but.............. no one uses that anyway.