Andrew,
Are you sure that's CAD? It looks more like Cardboard Rapid Article Prototyping, which I do a lot of.
....In fact, most of my modifications start out as CRAP and (sadly) many of them never get beyond that stage!
Have know idea why the above comment was posted? Andrew, what's a trailer like yours go for?
Curious as to why you guys don't flat tow?
Would you recommend MS ?