I was curious how is like to live in a camper. You can keep a small car and if you already have a trailer, you can build your own camper module. I do not know any company which can offer this kind of module. 

The module itself can be built with plywood and be covered with epoxy-glass fiber to reach water tightness and to improve structural rigidity. It can be cool to have an off-grid unit which can be installed at any site during winter as well.

I have 2 versions here. The bare minimal one has still side door to get in/out car like (and to keep structural rigidity), loading space 2050 (L) x 1090 mm (W). The second version is slightly longer front and back. With loading space 2050 x 1250 mm. Both versions have adjustable legs to help load/unload the module to the trailer. The modules were designed for standardized basic Euro trailers (up to 1500 mm = 4.9 ft of overall width). Interior got rails at different levels to slide interior components freely. This way the interior is very flexible to setup. See the basic renders. The yellow poles are for perspective = 180 cm of height (5.9 ft).