I personally am looking at ideas to downsize tiny. This one is 8×8, and has a sleeping loft that runs length-wise instead of width. The kitchen and toilet areas are behind fold or swing out doors to one side. All of the appliances are the apartment sizes now available, many are 18″ except the tub.
Yes, that IS a tub! There are clever RV tubs that are very small. This one is 32″x 24″ and I put it under the tiny stairs. The windows at the right of entry are pretty much floor to ceiling and I would also add two mini dormers to extend the feeling of size inside. The broken line in the middle is the loft, which is open. The ceiling would be under the 13′ of most, probably somewhere around the 12’6″ mark.
This one would be easy to tow and less expensive to build. Ideally, it would be tow-able with a smaller vehicle and be towed more frequently.