I've got an Isuzu Vehicross with a rear-view camera. In Japan, the truck comes with one standard, but the on-board video also tunes in TV, which is a no-no in the US, so they had to strip the imported models of the video. There's a cubby-hole in the back, however, which fits a wide-angled X10 camera just fine. I've had no problems with the X10 in bad weather, and the cameras are pretty cheap. You can either send the signal to an on-board VCR or directly to a dashboard video monitor.
Jason