what is the shortest class c that people have used?

When we first got married 45 years ago we bought a 1959 international 1 1/2 ton four wheel drive truck with a chassis mounted 10 foot Cab Over camper on it. The original owner had it custom built to travel to Alaska each year on fishing trips. It would be considered a Class C by todays standards. It was great for a young couple with no kids. It had an over cab bed and a sofa sleeper in the living area. A galley Kitchen with propane/12v fridge. We took a closet and turned it into a shower with portapotti. The old propane lights as well as 12v lights.

It was perfect for weekend trips. We did take it on a 2 week trip to a lake that is 500 miles away.