My buddy owns this site. try these:redfire GT said:
http://www.shelterworld.net/page/S/CTGY/SP_SML
This is probably one of the best for cars, if you have the space:
http://www.shelterworld.net/page/S/PROD/SP_SML/PB01010R4N
These tend to be less expensive:
http://www.shelterworld.net/page/S/CTGY/SP_CAN
This is good if you are looking to save money:
http://www.shelterworld.net/page/S/PROD/SP_CAN/1820CC
Finally, give him a call. He said he has some newer items in (not on the website yet) that would be good for my car, but I don't really have the dough right now ;(
Last thing, most of these products are NOT like the cheap POS you see at COSCO. It's real galvi steel, not powder-coated crap. If you like what you see, send him an email to ask the weight of the overall product as delivered (give him sku/code and description), the thickness of the steel, the thickness of the cover fabric. This is strong stuff, and the "fabric" is actually made from very strong vinyl, like a circus tent. My experience (used to sell 'em and install 'em) with these was very good. A couple friends bought them and loved them.
Good luck.