Jim,
You might try Friction Materials in Long Beach. 562-436-4224. They can still get the asbestos lining. They do their own bonding and/or riveting. We used them for all our brake relining for cranes and industrial equipment at the LB Navy Shipyard. Not sure what the criteria is for commercial use, however.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine