shawm; the ultimate drift boat material IMO would be roto-molded plastic like the material used in Old Town Canoes.
I have built "plugs" before but it was a very long time ago.... we made a "male" mold for a 12 foot barnegat bay sneak box and then made two female mplds from the plug for a top and bottom. I did this with freinds in Jersey but then moved to Maine and lost touch with them over the years.... they only made a handfull of duck boats from the female molds, I took the male plug to Maine but eventually junked it.
My freind Mike in Maine who used to own FLY Fishing Only fly shop in Fairfield also made a Tatman boat by himself and it;s beautiful.... he later bought Jeff's boat after Jeff lost his guiding License for "Rowing under the influence" of POT. Idiot.