I looked into adding one of the totes to my toy hauler that are legal in all the states and found the cost to be rather high - Like some others, my travels take me to places where double towing is not legal and is not an option for me. I also decided that wanted to keep my toys enclosed out of the weather and out of sight which nixed the idea of an open transport deck of any kind.
I went to a large truck camper towing an enclosed trailer to get more garage space yet keep my overall size down. I now have a 20' dedicated garage with 20' of living space in a combined vehicle length of under 50'.