I could probably build a fou-wheeled vehicle powered by compressed air provided with a few things I'd need, but not likely a very good one... Doesn't sound too hard at all actually, at least not to make a crappy one.
ANYWAY, that sounds like a great idea, if they can make ones that reach some 90 mph or so they'll have a market if no oil-giants buy all the rights and patents and stuff and hide them in a locker in a cellar in a fortress in a cave in a mountain that's really hard to get to.