[Excaliber]

That may be the key, that you built it. The MSO would deal primarily with the frame. Knowing what to say and how to say it would go a long way toward getting around the problem. That same rule applies here in Hawaii as well. I can build my own trailer or frame and declare it as such. But if I walk in and say I bought this frame from a manufactuer and built my trailer, that won't fly.

If your lucky, they may never ask about the frame or major components, just ask for reciepts. I would be careful to not go into details any further than I had to.