This is something I've always been curious about. Basically what is the price range from worst to best, how many options are there, and what companies make them. I've always wanted to get a system but never really looked into it. One of the funniest things I've seen was a 12mm camera (old big movie camera i think) mounted on the roof of a class 10 when the 500 was started south of Ensenada going up the hill. That was classic.