You could always add a wireless transmitter from the camera (powered by reverse lights), and then plug the receiver in the 12v outlet with a wire to a separate screen on the dashboard or air vent or something. Not the most aesthetically pleasing solution but it should work, and you could install it yourself.
You can use any stereo that has a screen and back-up camera ability. You can also get some that show it on na new rearview mirror. I would suggest going to a local car stereo store and seeing what they have that you like.