Hitch?

If you know you aren't going to tow anything significant, then get someone to actually custom build a hitch for you. I bet one of those speciality trucker stores, or just someone with serious welding skills can make a simple item that bolts btw your frame rails and doesn't require any sort of holes being drilled in the truck or bumper. Maybe they can find a simple support somehow from where the bumper bolts mount to the body.

I remember in the 80's, many of the low rider trucks used to have their receiver hitches hid behind the license plate and put a spring loaded license plate holder on the car so all you had to do was swing down (or up) the plate and plug in the receiver. Maybe someone can create you something like that that wouldn't be visible when not in use.