As far as I know, no Android device is currently powerful enough for that. There is no Xbox emulator that I know of that has been ported to Android.

I think its way more work than it's worth for devs to do. Especially since they'd be doing it without pay with the legality issues around emulation. And it'd be extremely difficult and slow to get it running smoothly. Iirc it wasn't until the last 4 years or so that any major breakthroughs allowed games to be fully playable and smooth on emulation for PCs