Car haulers are typically rated for more payload with larger garages and based on commercial trailers verses toy haulers that are more RV based with a garage.
I originally was looking at these to upgrade my toy hauler when I started to to run out of garage space. The toy haulers that were open floor plan and had 18' or more garage were too heavy for my 3/4t truck, so I found these LQ haulers that could be 38' long yet 9000 lbs empty even when nicely outfitted. With these haulers, the draft is lower too so it would have worked well with my 15,000 lb gooseneck tow rating.
We decided to split off the garage from the living space by buying a truck camper and towing an enclosed trailer instead. This works better for us since we don't always need our garage with us, but I would have no problem revisiting this option in the future.