there's never stupid questions...
1.- There's any mame who runs UMK3 and Azura Blade ?
coinops plays umk3 but i don't think it plays w/ sound. azura blade plays in final burn legends but it's a memory hog. it plays in coinops too using final burn legends core, still a memory hog but i can't confirm at this time.
2.- There's any emulator for Crusin Usa (Ultra 64 version, not Nintendo64)?
3.- There's a Nintendo DS emulator ?
on a postive note, there is a saturn emu now. if you have a 128m modded xbox then it works ok (normal 64m xbox strains to play it, but it's the thought that counts). there is also a panasonic 3DO emu (memory again). and the atari jaguar is in it's beta stages.
it's all happening at emuxtras.net