Here are a few of my ideas:
1.) Satellite radio.
2.) real mattress on the sofa bed.(air matress is worthless)
3.)switch to turn of led brake lights and lights on front top so that they stay off after you close door.
4.) battery disconnect switches for all batteries.
5.) anti-freeze by pass valve.
6.)engine heat shield.
7.)door alarm on the fridge door.
8.)light switches mounted lower so that children/grandchildren can turn on/off the lights.
9.)Microwave mounted lower.
10.) outside tv mount(for tailgating of course)
Last but least 2 dream items:
self cleaning carpet