I think it was Grainger, Fastenal, or one of those type parts houses that sells raw friction material that you can cut to shape. They use it on antique mopeds and get good service.
If I can locate more info I will post it back here for you.
Good luck
rc
Aw heck!
You are in Burbank!
I just noticed that...
You can get anything in the WORLD without going far!
Just ask a couple motorheads where to look.