CB/HAM antenna mount for sure. A few have done it, and I was going to do it forever ago, but had such good luck with my roof mounts, my cowl mounts, and my dual roll-bar mounts, that I never got 'round to it.
My table/stove/camping mount was for the back of my Hanson bumper mount tire carriers. Either the single wide swing, or the dual narrow swings (my preference). But never quite got round to that one either, even when I worked at Hanson! Insert rolling eyes here...
I think your idea of a combo mount for either a table or grille, or whatever, would be great.
I always thought of things that were hanging out on the tailgate side, but looking at your picture it would make sense for something to swing out to the side (think ranch-hand carrier) instead. Whether it's mounted all the time and just swings out when needed, or just the mount stays there for you to stick whatever appendages you have in the hole only when needed.
Great subject for discussion! Don't remember the last time we talked about them thar mounts.
Paul