I saw a ty once, owned by Jeff Shuffleton now...
Had a clever custom hitch.
They took a class 3 reciever (just the socket) and mounted it facing down, behind the cover...
Then they took 1" or so square tube, welded to that extending to each frame rail. Couple tabs and it bolted to frame...
Very simple, and TOTALLY hidden. My buddy owned truck for few months before we found it.
It would require custom hitch, but that would be easy also.