In Reply To #2
Just because it runs OS X doesn't mean applications will run the same. The iPhone uses ARM architecture (same kind of processor the DS has), the newer Apples use x86 architecture (what's commonly referred as "Intel Based"), whereas the older ones used PowerPC (a type of RISC architecture created by Intel), the ones in the 80's and early 90's used Motorola 68000 architecture.
Porting software is rather easy, if it doesn't use architecture specific assembly or architecture specific tweaks. If not, those parts need to be rewritten. Chances are, the complex emulators are using some architecture specific code, thus that would need to be replaced. Not only that, you can't exactly compare a CISC (such as the x86 family) processor to a RISC processor (such as ARM), their computing power is completely different, they do the stuff in a different way, an ARM processor at 266MHz is comparable to an x86 processor at 500MHz. Yes, ARM processors are that powerful. But other optimizations need to be taken into account, such as RAM optimizations, screen optimizations and input method optimization.