These are called RV Port Homes. They often feature smaller square feet, as you have the RV for extra bed and living area. The cost is more because you have a larger roof area.
Bradleybuildings.com has several floorplans available as a kit, but only in a few SE states. If you can find a builder, you might find floor plans online. Check out Morton Buildings in the eastern half of the US, and a few western mountain states.
Here is a drive through design I really like. Carport and storage on the right, living area on the left, loft area above. Garage doors would make it perfect!
Bad decisions make great stories!