Yes, You Can Make a Utility Trailer Camper to Sleep Your 8 Kids. Wow, It's Even Got a Bunk Bed. - http://www.doityourselfrv.com/yes-can-make-utility-trailer-camper-sleep-8-kids-wow-even-got-bunk-bed/
And if you were planning a remodel, slide out surfaces in general can be huge space savers:
Build A Camper Trailer Plans DIY Free Download tool cabinet ...
This is Daniel Mohr’s DIY Zen Den Micro Camper. It’s a micro traveling camper built from recycled materials. I built my Zen Den from scratch to travel to remote destinations and have a …
FiveJoy Instant 3 Person 3 Season Dome Tent - Double-Wall Two-Door Bathtub Floor Freestanding - Set Up and Tear Down in Just Seconds : Sports & Outdoorsread more
Hütte Hut: A high-design trailer fit for the beach.
How to build trailer couches - Google Search
camper trailer wiring setups - Google Search
With a little welding and some wood work, you can have your own off road teardrop camper.
DIY Camper Couch/Bed with storage. Photo 2