portable emulation

I wasn't sure where this should go, but because it's chiefly about computer tech and not images I decided to put it here.

'Kay, the thing is that I want a laptop or some kind of portable system that is just powerful enough to run a Super Nintendo, NES, or Gameboy Advance emulator smoothly, could be old, preferably compact (though I guess "old" and "compact" are not renowned bedfellows), with 2 or so USB ports to plug USB controllers into. 

Would this be possible?  As affordable as I'm hoping?  I know nothing.  Help me!

VisualBoyAdvance will require at least about a 800Mhz system for full frame rate (could be less depending on internal video hardware - which won't be good for an old laptop)

ZSNES will require a 400-500Mhz system for full frame rate.  Maybe less if you use the DOS version, but be sure your sound hardware is SB16 compatible.

I barely got fwNES working at full frame rate on my old mother-in-law's 233Mhz system with a crappy S3 video card.  I was able to get loopyNES working at full frame rate under DOS on my old pentium I 120Mhz.  Worked decently under Windows ME as well under the same system.  FCEU Ultra, forget it, need 500Mhz.

VisualBoyAdvance will require at least about a 800Mhz system for full frame rate

I sometimes see dropped frames with a 2Ghz machine, so that 800Mhz is far too low.

ZSNES will require a 400-500Mhz system for full frame rate.

I used to run zsnes on a 400Mhz system, and it was dropping frames constantly too.

lol buy an actual gba

>>3
It needs less if you run in a very small window.
That sucks, though.

>>4
Then he can't play SNES games.

don't know if gba works on it, but nes and snes work on the gp2x. there are emulators for NeoGeo, Sega stuff, PC-Engine and some others.