Look at the car hauler style trailers with living quarters from Work and Play, Feather Lite, InTech and Millennium. They should have what you are looking for and some offer nice interiors while others are more utilitarian.
We went from a toy hauler to a truck camper towing an enclosed trailer. We like it enough that we are upgrading our current truck camper with one slide to a make and model with three slides this Spring. It gives us the flexibility to bring the garage along when we want it and leave it at home when we just want a quick unencumbered getaway.