I had also looked at a rack called "Jack-It" by Lippert. It fits over the tongue jack of a TT, and can carry two bikes. Seems pretty slick!
But, with upgrading batteries, etc., putting the bikes there may begin to push my truck's receiver rating. I do have gobs of extra truck payload, though....saw a post elsewhere where someone put a receiver between the pickup bed sides, just behind the rear window, and then used a conventional bike rack (since I have 2 of those!). Sure, have to get in the bed to load/unload, but since I have the Ford "old man" step to get in, shouldn't be much of an issue. One of the many things to do - go to the local welder and see what they can make up, for how much. Only challenge will be making something that can clear my roll up bed cover, so I can continue to use it while towing and carrying bikes.