A built in knife holder around the stove area would free up space in one of the drawers.
Actually, I did like that one in my Adventurer. It was behind the stove top.
Back up cameras are another issue. Trouble is you have to determine if they are standard wiring for a wired version. Wireless would be better if you can perfect it. I know you said you had a 9V one working, it just occured to me that you can get a cheap transformer from radio shack to drop 12V DC down to 9V.
I much prefer a sliding bath door. I found the hinged one in my Adventurer a pain. Each to his own I guess.
Another possible cheap option, a 12 v computer fan in the fridge compartment to help cool the condensing tubes, operated by a switch on the inside. Might be useful when camping in extreme heat to improve fridge efficiency.
Cupboard TV with a built in DVD player to cut back on wiring & remotes. Go to a Radio CD player with an audio input jack (newer ones have them). This will enable hooking in an mp3 player or satellite radio receiver.
Small 3/4 or 1/2 inch plastic PVC (like electrical conduit) conduit leading from underside for the overhang near teh truck cab cab to roof that a satellite antenna extension or GPS antenna extension could be fished through later. (or cb antenna wiring) It could be open at each end, as long as it does not permit water ingress into the roof itself. This would also allow back up camper wiring to be fished out of sight & run along roof top. later.