Ally
Yes, I agree there is a risk to the builder which is why I mentioned the possibility of a third party holding account for bespoke orders. The customer would deposit the money with a third party (maybe a regulatory body or similar) which would protect the builder from a disappearing customer. If the builder had fulfilled their side of the contract by building the boat to specification then the builder would get their money.
Most boats are not terribly bespoke though, as most builders seem to build to a set pattern, and so I would have thought there should not be too much problem in