That is really a slick design, I like the box concept. But, I have to ask about the safety of hanging a propane tank off the back of the trailer. I only ask this because me and my M416 trailer got rearended once. Fortunately the Honda was riced out and lowered so it slid under the trailer. The *** end of my trailer came to rest where her windshield met the roof.
Had it been something with substance, say an F150, lord knows what could happen.
Really am interested in the price of the setup.
Wouldn't bother me at all, might make tailgaters a little more wary though!!!