Not sure about the whole gay/jeep thing either, from my experience, not only are hot chicks driving around in jeeps, but they also seem to be attracted to guys who drive said jeeps.
Gotta watch out for guys driving in those new Beetle's though, not saying they're all gay, but a good majority of my gay friends know someone who has one and/or wants one themselves...
btw, that Jeepchicks site is pretty cool.