I mounted my Home Depot Bucket Head Vacuum in the available space under the bed behind the refrigerator. I then spliced int the existing outlet to add a switched outlet between the water heater and fresh water tank. I used a shop-vac adapter to make the external fitting and put a nice trim plate on to finish it off.
Final trim fitting and power switch:
Bucket Head mounted and hose attached to adapter:
A plastic tub on top of the fresh water tank holds all the vacuum accessories:
Here is the vacuum all setup with an 11' hose that can reach everything inside the trailer:
When I get more time, I plan on putting another shop-vac adapter on the exhaust side of the Bucket Head and mounting it inside the storage compartment so that I can use with the appropriate adapters to inflate air mattresses, etc.