For native resolution? None.
For stretch, a few that I know of.
(snes)
[url=http://www.pj64-emu.com/]Project64 Nintendo 64 (with a plugin)
VisualboyAdvance Gameboy (normal/color/advanced)
PCSX2 Playstation 2 (with a plugin)
ePSXe Playstation 1 (not sure with this one)
It is a long time ago that I tried this. Remember, don't ask for roms here ever.
If you search in the triplehead forum you can find a post, of someone who had zelda, ocarina of time working in triplehead (only the 3d part worked, 2d was simple stretch)