I've seen one installed on a EXPY for sale at the dealership. They place the video camera adjacent to the license plate so it looked like a key hole for the lift gate.
Considering how high the rear sits up and how difficult it is to see out the rear, this might not be such a bad idea.
I knew ahead of time that backing up was a chore in these trucks, so that's why I got the rear sensing which helps a bit.
A rear view camera would be nice, but it's always difficult to judge depth when looking at a monitor. Still, something is better than nothing.
I guess the next question is, how much does something like this cost?