If someone is making a trailer for long distance trips, where they camp along the way, they may want to make a trailer long enough to sleep in. You may even make one which is shorter for travelling, but folds out to bed length. You could have storage space under the bed.
I've been thinking along those lines. Not necessarily to be able to sleep "in the trailer", but to use the trailer as a platform for a pop up tent.
Kamp-Rite made a trailer version of one of their cot-tents a few years back. They had problems with the axle mounts/articulating suspension breaking which is what killed the production of them. Instead of a redesign they canned the whole concept.
https://newatlas.com/midget-bushtrek...trailer/22167/
I like the idea of being able to fold out a tent and bed. I could have used that on my trek last fall. I am not sure how to go about it, though. The Kamp-Rite tent cots are quite heavy for what they are, but I am not sure anything else comes close to that concept. If I make a fold-out platform on which to set up, say, a 1 person tent like a Hubba Hubba - then I have the set up/tear down time, maybe more, as if the tent were set up on the ground. So efficiency-wise I am not gaining anything. That would have to be part of the set up - an efficient means to set up/take down of the tent and gear to spend less time between riding and sleeping and sleeping and riding.
I wouldn't be opposed to experimenting with coroplast (think Paul Elkins). However, I am not sure of a way to make a structure that will collapse down. If I were making a "bike camper" that could be built and left set up that is one thing. That doesn't work with what I am trying to go after, however.