Sorry I was the one that brought it up. I looked at the rules I dont think you can change the material, not that I see a tech insectors pulling brake drums and testing the linings at the regional level (maybe at the runoffs?). As far as an alternate lining material I would think asking some of the brake companies (willwood,AP, ect) what they use for there brakes might be a starting point? Though it may be a waste of time. Still if the cost is not to much refurbishing them still will be better than running the steel ones (lots wt+heat)thats why the 510 guys always tried to upgrade to the "Z" drums they are superior to the steel ones.
Has anyone looked into any of the JDM markets there is a lot RESTO companies making parts for the JAP cars in Japan. I have seen them talked about on the Nastalgic japanease car page? Just another thought for the OEM parts