As far as I know, mophun is even more closed source than anything else mobile phone related, which makes it
damn hard to port/adapt it to any other platform. I once read about how to become a mophun developer, you'll need to come up with a good idea, and the makers of mophun decide if the idea is good enough. Then, you'll need to pay a lot of money for the sdk and development environment. After developing your game, they'll check out the quality of the game and ask for even more money, and so on...
It's just too closed source to work with on any other platform.
Anyway, most midlet/mophun/symbian stuff sucks very hard, so why bother doing an emulator for it?