I built a custom computer system for my friend's RHD Civic, we got a small webcam and molded it into the left mirror that way he can see oncoming traffic via his 7" screen. Later on we're going to try and get ahold of a small, spy-like camera that has some sort of night vision mode.
The whole setup only cost about $500. Not bad for a full-fledged computer that integrates with the car's stereo (think 80gb of MP3/Video storage

), GPS, voice recognition(can be run almost totally hands free), and wireless internet acces
Oops, sorry to go off on a tangent like that.