JohnE is correct. China still has them. I bought a handfull last time I was there, but sold them to another rod-brake enthusiast who needed them. The Chinese brakes aren't too bad. The brake pads themselves are of some kind of laminant. Heck they might be made from cut-up old tires. Anyway, they work.

If you have any friends in China or who are going to China, they can easily get you rod-brake pads at any bike shop.