Hello David
I have the same question you have regarding the rear camera and a shell. We just picked up our new AT4 in AR, driving from NC over the weekend to get the color and engine we wanted. I want to put our dogs in a shell when they're with us, but don't want to lose the camera.
What manufacturers are you looking at for your shell/topper? I can ask the same questions of the dealer here and maybe get them working on a solution.
Thanks!!
John