Don
We do a limited number of custom trailer builds every year. You can read about the
motorcycle trailer we built here.
The number of custom trailers we build is limited by our work load.
If you have the basic plans of what you want it makes it straight forward. It's when potential customers have no idea what they want that the design gets costly.
One off custom trailers are expensive as there is no way to spread the R&D over a larger production run, but that's just the nature of it.
If you send me the Sketch Up drawings I'd be glad to look at them.