There's an active thread right now on the subject of temporary/removable tailgate tables. That thread has got me thinking about several designs for removable table designs but rather than hijack that thread I'll post about it in this thread. The original thread is here:
https://www.expeditionportal.com/forum/threads/temporary-tailgate-table.216511/
I've got two different design ideas - Design 1 would slip over the tailgate and not require any other attachment to the tailgate. Design two would use existing holes in the JK and JL tailgates for thin mounting rails that the table assembly would slip into, not unlike the clip-on tables that are part of the MORryde trail kitchen.
The benefit of Design 1 is that there is nothing to install - the table would simply slip over the tailgate. Design 2 would store in less space because the brackets that go over the tailgate wouldn't be needed.
One other feature of both designs is that unlike "fixed" tailgate tables, since this one doesn't have to fold up against the tailgate so that the tailgate can close, the brackets will allow for multiple table heights. The table could be positioned at the bottom of the tailgate like conventional tailgate tables, but could also be attached in the middle or at the top, and the mounting brackets (or hooks) could be designed for mounting the table at multiple heights.
An inspiration for Design 1 is a folding marine ladder. These have hooks on top that fold flat for storage and unfold to hang over the gunwale of a boat. The ladder pictured below has 4 steps, 2 of which unfold, so imagine those bottom steps are the table and are set up so they only unfold 90 degrees. The shape of the hooks would be very different for a tailgate table because the tailgate is much thinner where a ladder would have to hand on a boat, but the fold-flat idea would be the same.
An inspiration for Design 2 is the Trail Kitchen, which has optional clip-on tables. I don't have the Trail Kitchen in a Jeep or trailer at the moment, so here it is on a the cart I keep it on when it's out of the Jeep to demonstrate a clip-on table and clip-on stove: