Unless you're going to ship the construction modules to Mars (or I suppose India) why would you bother? I thought the "great thought" of molded was NO seams. I don't think I'd design my modules around the constraints of 40 bucks worth of welded side rail on a twinky landscape trailer. Oh, I get it! The idea is that somehow you can jack that 300# "furnished" box out the back and then you still got a nice little utility trailer for hauling sand and gravel (after you spend another 150 bucks on plywood floor and sides). People have more fun than anybody!!