I just realized that the late '80's-early '90's Mercedes 300E that we were discussing in a thread a week or two ago might be a good option, if you don't have a problem with buying an older vehicle. You can find plenty of low-mileage 300E's if you look hard enough. The gas mileage is good, and I'm told that you can use regular gas. Repair costs might be higher than for some cars, but the initial investment is modest. There are plenty of these running around with a couple of hundred thousand miles on them, and I don't think that too many of them are rattletraps. If you're concerned about fuel economy, check out the diesel version, the 300D.
http://www.tdpri.com/forum/bad-dog-c...thusiasts.html