Ons, do a google search for www.trapperman.com + trapper hat. Theres a few leads on hats, hat makers and patterns. Wolfwoman does some nice work with your pelts or hers.
Also, maybe closer to you is is glacier wear in ME who will also make a hat for you with yours/their pelts.
Trapper man though is the place to root out a pattern, just need to see how deep the hole is to find it. I know there is at least one pattern on there cause I read the thread this past January.