The situation over here in the performance end of the market is very different. Many of the super-skilled people who work in the industry here work on a consultant basis, or have companies who contract
to builders, and these teams work in a number of industries. I can think of at least 3 reputable yards who use various contractors to do specialised work for their projects- Gunboats, R&C, Southern Wind
or Maxim being names that immediately come to mind. They all use contractors and that on an as-and-when basis. FWIW, RSA83, aka Shosholoza was built in the yard of a builder
who had space enough to sub-let, and who put some of his work on hold for the 93 days it took an assembled team of experts to build her. Cogitate on that for a concept- I doubt many other campaigns have ever done that!
Just be careful when looking for a custom job that you are getting the best team actually doing the work. Custom doesn't mean "mass-produced hull
with personalised interior", like most "custom" jobs are. Pushing the design-envelope, or straining the limits of craftsmanship are what "custom" means. If you are seriously looking around, then why not put your own team together and project-manage the whole thing?