I picked up the shell for a Yuppie Wagon from a guy in Atlanta who is no longer building them. It is basically a 7' x 4'+ x 4' molded plastic shell that is quite thick weighs about 110 lbs. They were used to make motorcycle and mobility trailers and could be used as a small enclosed trailer to haul just about anything that will fit.
I ended up using a Harbor Freight 4' x 8' trailer which I cut down to 4' x 6'. I finished assembly and today I mounted the iron angles to which I will attach the shell. I ordered a teardrop door from Franck at Vintech and will mount it on the back. I have decided I will insulate and finish the inside and probably add a vent/fan and two small windows.
This will be a minimalist trailer when I want to go camping by myself or with one or two of the Shih Tzus. We still have the T@B for when Jackie and I and the pups all want to go.
Here are some pics of the start so far...