I'm looking on craiglist in the Bay Area. It is pretty frustrating, I'll admit.

All those things you describe would be nice but any service like that would inherently restrict you to those seller savvy enough to put all that stuff down. Most people don't seem like and so you'd be only scanning a small subset of available cars. Is having them presented in an orderly fashion worth having few listings - of course not. Yeah, the sellers and buyers are a real mixed lot. But an organized website can't conjure a whole new pool of buyers and sellers into existence.