I'm looking for a lightweight rack that somehow hooks into the trunk lid of the car. I'm leasing, so don't want to do any permanent alterations.
I bought this hitch and had the local Toyota dealer install it: It was a really, really tight fit at one point they weren't sure they could do it without the bumper plastic not staying joined. But they kept at it and it hasn't had any problems. Installed a Saris hitch rack.
Check out Seasucker for something very non-permanent that you can take to another car, and be able to hold your bikes with confidence. Very pricey compared to a dept store trunk mount, but compared to semi-permanent roof racks, or having a hitch installed this is pretty affordable. I'm new to this forum, so I can't post the link, but a simple google search should yield some results as well as reviews. I was pretty skeptical at first, but I've been using their three bike holder all spring for road/cross bikes and its great!