Take a look here, something might work.
https://www.tadibrothers.com/categor...camera-systems
I wanted a higher mount camera to show the traffic as well as posts.
If your camera is wireless, all it needs is 12V. It can get it from the marker lights or the clearance lights, 12V is 12V.
For me, the license plate braket is low and on one side.
Can you not mount a wireless camera above a clearance light or over to the side?
It'd just be a matter of snaking a wire out a hole and attaching the camera to the body. If your body is fiberglass you'll need a ground also.