Set top MAME box

I was lurking in the Gaming forums and saw a post about how someone wanted the next gen consoles to come out with PC emulators.

That got me thinking. I'd like a MAME box to connect to my TV. I know I can get an old computer to do it, but that seems like overkill.

I wonder if anyone out there knows of a hackable device that could double as a MAME box. Something like Raspberry Pi, or an Ouya, (when it's released), or even using an old smartphone to run the emulator.

So, what do you say do it yourselfers? Anyone got any ideas about how to best do this?

(If anyone thinks this would be a good idea for a sellable item, go ahead and put it on Kickstarter, just give me credit for the idea, that's all)