well i don't think the resolution is the problem
1.the emu could set it lower
2.many n64 ran at 320x somethinh
and isn't the n64 cpu 64bit like the name says ? and as you saidthe buttons ...
What about a cps1/2 emu ? I would kill (or atleast donate) to see Puzzle Fighter on the gp32 :D
Final Burn is a cps1/2 and open source !
http://www.finalburn.com/source.html