Just a quick update...
The electric brakes on my trailers operate fully at less than 10 amps.
I am currently mocking up the box for those that are interested. I am mounting everything inside a plastic ammo can. I did some looking and that seems to be a popular case for various companies as well. I am sure that pretty much all the companies have similar products. The cost of these test boxes range from 100-200, but none are wireless.
The box will have storage for the power cables, wireless remote, and adapters. If anyone is interested in building one I will send you a parts list when I have finished.