The only core that could be ported that I know of is mupen64 and I think pj64 is heavily tied to Windows last I checked.
As for his emulator, even with a new DeSmume core I expect that this will need a lot more work to be considered usable for a lot of games. 2D performance might be good but I really wonder how well the 3DS will handle the overhead. It's certainly interesting and a good learning experience though.
@MasterFeizz I'm looking at citro3d and trying to get a good idea of what best practices for it are. Would you recommend drawing to an off screen buffer first? Does citro3d have a buffer swapping method? I can't find an API documentation.
I may not have time to work on this myself but I'd like to give
@shutterbug2000 some guidance where I can.