Original Xbox Viable for Light/Medium Emulation Use?

So, for a while now I've been wanting to put together a box of some sort to play old arcade stuff and maybe some SNES/Genesis stuff but nothing terribly recent. I don't have the time/money/energy to build a full blown MAME cabinet. One day though . . . .

What I have been thinking about doing is getting an original Xbox console and modding that. What I like about the idea of using an original Xbox would be the fact that once it is set up it would be all nice and self contained. What I'm wondering though is what level of performance can I reasonably expect from an original Xbox? Obviously it's not going to be able to run a good amount of MAME content but how well does it do say CPS 1/2 and NeoGeo content? What about the 16 bit systems? I'm just curious how viable an option the original Xbox is when it comes to use as an emulation console. Any comments are greatly appreciated. Thanks!