This is kind of "way out there" but several people claim to have working prototypes. I've posted it before, and most people have been skeptical, but the flip side is the people developing it say that they drove cross country with using any fuel whatsoever. You be the judge.
IMO if this works it's the next "big thing". But it's unreliable at best right now.
http://energy21.freeservers.com/as101.htm