What... you don't have one in the backyard :-) We are reusing the Viosport cam from another project. We wanted a good quality image because we would like to do some other image processing/feature extraction projects with the Mac mini setup...not just look at fuzzy images of the rear of the vehicle.
If you are just looking for a rear view camera...there are tons of them out there for less than $30 bucks (EBay). They just didn't provide a usable image for processing.
This Cam is quite good, got is from a ebay seller in Hong Kong, works well at night, not used very much in car as I only have a small hand held tv, I will link it into the back of my soon to be aquired touch screen but for the mo i have it pointing out into the garden to look at the ducks there at night