Not to condone piracy or anything, but there are a plethora of SNES emulators available on the Nintendo DS. Some of these (such as snesDS or SNEmulDS) do have fully working games that run on the DS. The real problem here is that most of these emulators have stop being updated so compatibility issues aren't being resolved.

shhh... dont give the RIAA any more ideas on justifying DRM.