I just came across this vendor http://www.homegrowntrailers.com/sales/. You can watch a short video here https://www.indiegogo.com/projects/homegrown-trailers#/.
I was shocked at the price $28,995 (+ sales tax), especially for the off grid package for $7,500.
Worth checking out for ideas, looks like they are just starting out so lots of luck to them in their new business venture
Dan