What a treasure trove of great ideas! I like the complete pull-out kitchen on extension glides the best.
Not so much for tents of top of things. We camped next to someone that had a roof-mounted tent on an FJ Cruiser and it seemed like a long, fussy process to put it up, much longer than a land-based tent. Ditto for folding up.
That said, if I were camping in a place with large predators and was uncertain of my place in the food chain, a roof-top tent would start looking pretty good.
We have a friend with a roof-top tent that he has alterately mounted on his SUV or a little kitchen/gear trailer. Both worked well for him.
The
Honda E Camper is also a brilliant idea.