Something I'd like to see....
While going through the refrigerator, water heater, etc. on our original '71Tradewind, it occurred to me that an integrated energy system for an Airstream could be a win. We burn propane to heat water, and heat ammonia for cooling, and many of us burn gasoline or propane to generate electricity and during the winter keep warm.
A small DC propane powered, water cooled quiet generator could produce electricity to charge batteries, and at the same time we could use the waste heat to heat water and keep the food cold; it should be practical to replace the furnace as well w/ a radiator setup, and replacing the AC might work as well.
Back in the 70's such integrated systems were described as "co-generation systems"; with the prospect of increased energy prices in the future, roving full-timers might find such a system useful indeed.