You may want to give this unit a try...
http://www.cctvx-cctv.com/carcorder.html
Basically its a Dual Camera Digital Data and Video Recorder in a box that fits on your dashboard and plugs into a cigarette lighter.
The unit records video out front of the vehicle as well as inside the vehicle (even at night with its IR LED's). Other data such as GPS, Audio, Time Date etc are recorded, so its quite literally a Black Box solution in the event of something going wrong inside or outside the vehicle.
Recording of images is onto an SD card, and playback is via a PC (Windows or Vista) each card can also be tagged with driver number, and cab details so a detailed log can be saved in data storgage for playback in the event of an incident.
Worth a look...
