I wonder if a product exists that is a little box that you plug a reverse camera and those little sensors that go into the bumper, and it outputs a video feed of the reverse camera + a sensor overlay type thing. That way you could have it wired into the backup inputs on a Z2 and when you put it in reverse, you get not only the camera, but also distance sensor radar things.
I found this:
But I'm not sure if it's quite the right product. Also, that link is from an exporter and you have to buy a minimum quantity of 1000.