Shop around, go to RV shows, try to figure out just how much space you want. Small trailers can be equipped with bunks, as small as 16-foot if you are willing to convert living space to bed space, and deal with a small kitchen and bath. Our family had an 18 footer that would sleep 10 (in five beds) after everything was converted and the bunks hung, but living space was minimal, we used it for sleeping at night and lived outside in the campground.
Is it enough to have the bunks, or do you want a bunkhouse with two distinct bedrooms, in addition to the living space?
Looking at a couple brochures from my last RV show visit, you can have bunks at 18 feet in Forest River's R-Pod, if you will accept a dinette converting to a bed, or a queen in a fold-out tent space. But the R-Pod has a very small bath, tiny kitchen, not much living space, it is for camping rather than living.
Skyline's Nomad lightweight shows two bunkhouse models (queen at one end, bunks and bath at the other, living area between) at 27 feet, a couple more at 29-32. Nothing smaller in that line, because all models have at least one permanent queen size bed.
At the small extreme, Casita's Spirit model has one dinette converting to a queen, another to a single, with a bunk installable above that. Bathroom is tiny, storage almost nil, living space is tight, but it will sleep four. That's either 16 or 17 foot, max 3500 pounds. If you give up the bathroom, you can have two more single beds, bunked, up front, to sleep six or seat 8-9 people.
Tom Test
Itasca Spirit 29B
