You guys do realize that the musicians rarely have much to do with how their videos look beyond "make me look cool", right? There's usually a Producer to crush the musician's high-flying expectations, and slave labor Editors to make it all comes out in the end. The musician will usually have a few scenes in mind, or a concept to illustrate, but professionals leave work they aren't good at to other professionals.
While the 'none' option would be most appealing, I think I'd be least offended by a Primus MMO if it has to be a musical celebrity. I imagine something like Conker's Bad Fur Day + Psychonauts + Day of the Tentacle, but with crafting and Buckethead.
If we're going for general celebrity status, Scott Bakula is due for some awesome. A Quantum Leap MMO gives me nergasms just wondering how they'd pull it off. As long as you can't leap into a Murphy Brown episode or Enterprise, I'd at least try it out.