Agree with trainjunkie. Try boat mold makers. That seems to be a bigger market.
You could also try Robert Johans, developer of the Nest Caravan, now Project Manager for the Airstream Nest. He is a member here and used to post a lot. His loyalties may have shifted. You may also find the answer in his posts here. By here I mean on fiberglassrv, not the link.
https://www.airstream.com/blog/story...all-big-thing/