Hello, Brad I am not positive of sure of your location. Your name and general local can be listed on your profile or signature so folks can help locate stock closer to you. The BR varieties are rare but there are a few out there and hopefully they can be spread around more. They are a beautiful color and deserve more folks working with them. Get in touch with Jeff Vance, hopefully he can point you in the right direction. I know he does not have any right now but he has an interest and has put some effort into finding out who and where.
Also, if push comes to shove, you can use some silver to reinvigorate them. Some of the original silver breeders used BR to cross, created birchens which is the silver version of the BR. These were used to better typy and reduce the Red in the males that often is an issue in some silver lines today.
Feel free to drop me an email if I can help. drccash@yahoo.com Good Luck! Don Cash