Nobody makes/sells the gm 15x5 brake shoes anymore. I've called several places over the past year and no one could help. I plan on sending my rear shoes to this local company to be relined.
http://www.cecofriction.com/index.html
Centric brakes makes 14x2 shoes for the front and dorman still makes all the rubber brake lines. Raybestos still makes wheel cylinders (although made in China) and can order them from Rock auto. If you need any help with part numbers just let me know.