i am currently in the process of building out our competition setup. I have not seen anyone with this idea yet, but here is what i am doing.
I got a Slide in camper (adventurer 80S) for my truck bed that has all the amenities I would need, AC, Shower, Queen Bed , Bathroom, TV and etc. (That was phase 1)
I am going to get a small 6X12 trailer just to setup a small prep kitchen and place to haul my smoker that will be towed behind my truck. My plan is to just put the ramp down and support with jack stands to make a porch for my smoker. Put a 10X10 over it and be done. My camper has a hot water heater and outside shower hookups, I am planning on removing the shower hookup and just put garden hose fitting on so I can run hot / cold water from the outside shower hookups to the trailer sink. I have a full shower inside the camper, so I don't think i'll ever use the outside shower other than for rinsing stuff off.
My goal was to keep the trailer light and maneuverable so its easy to get in and out of spaces and make sure I comfortably fit inside the comp area.
In my design was trying to minimize setup / tear down time at a comp and also store all my bbq stuff in the trailer so I don't have to worry about packing and unpacking for every comp. It will all be in the trailer ready to go when I want to go, just add meat, garnish and Ice!
I have other uses for the truck camper other than BBQ, so that drove my idea as well. It may not be the right solution for everyone, plus I already had a truck setup for the camper.