I found this site that carries Gentex equipment, there are other site out there though. They have the mirror/monitor like the one that comes from the factory. This mirror has a 2.4" display for the monitor. I believe there is a bigger one available, I think it has a 3.5" monitor. They also carry the 3rd brake light with the camera built in (apparently the factory system is over your license plate, next to the light.) The mirror comes with a 6ft wire that runs down under your dash and a 20ft wire the you would have to snake through your head liner to the back of the truck.

http://www.brandsport.com/gntx-50-genk242.html

http://www.brandsport.com/gntx-20-nav03.html