So far no built-in's. That doesn't surprise me. I would expect that many serious BBQ'ers would want more flexibility and not want to commit to a built-in unit.
Why?
The desire to upgrade to new technology; to have the best and most suitable gear for the purpose at hand.
Having gear that is modular and flexible so that your equipment can adapt as your cooking adapts.
Built-in is like having a built-in GPS in your car. 5 years later it is old technology.
Notice that I said many and not all or most. That was intentional.
I am a competitive archer. We see this all the time. The new stuff does not put more points on the scoreboard, but that does not stop folks from wanting it.
The difference is that I think there is still a lot of functional innovation going on with grilling; pellet grills being an example.
Some folks take pride in how long they have had their equipment. I am that way about cars. So I assume there are folks in both camps.