SO it seems they figured out PS3 and 360 Emulation.........but you'll need Watson to run the emulators. A few other emulators are on the way. Interesting Video
My understanding is that it's recompiled to x86/x64 from power pc (but exact same code) and then there's a mini 360 environment also made for x86/64 that runs it. So its basically xbox 360 running on x86/64 natively, not emulation.
It is amazing that they can even do that to begin with on the XBONE. More shcoking though is that it took this long to get a working Original XBOX emulator working. Interesting times we live in.
I am pretty surprised that the Xbox seems to take a lot longer than the PS2 did for emulation (sure the PS2 wasn't as powerful, but it had a comparatively strange architecture). Though in all honesty I wouldn't be surprised if in 15-20 years XB1 and PS4 emulation are a common thing.