I am making one at the moment but doing so very slowly.
If you like to help me write joypad, d3d code or help me port it to a non windows system let me know by sending me a PM or posting to this thread.
the nes emu that i am working on is portable. right now it does compile and run on x86, ppc, and mips. linux, unix, and osx. mine is still in develpment though. but what i find is that for someone to know enough to help, they have to understand it well. to understand it well, they have to code it themselves to learn it. but if you want it portable, get the nes core to compile anywhere. you probably need these test platforms too. mine is using sdl with the core separate. the core can compile and run without sdl or any gui, just wont see much at all. but works. i think once the basics are coded, i would like to work on something that compiles and runs anywhere. to do that i would need multiple libraries. like opengl is next on my list.
matt