I've planning an expedition trailer build for some time. I really like the idea of a folding or expandable hard side / roof trailer that has the ability to add canvas area. I'm not really sold on the RTT yet for everyday expedition use. I was thinking of something like the attached pic. The TVAN is not available for US import is my understanding and I was thinking of building a trailer similar to the TVAN design utilizing a square tube aluminum frame covered with a product such as Nida Core structural panels. Any suggestions or comments? Am I going down a road of significant work and cost when there are ready made solutions already available?