For you guys doing the nylon rollers, they are easy to make yourself if you have a lathe (either metal working or wood working) or a drill press. I just buy nylon washer stock from the hardware store, chuck them in the lathe using a bolt as a mandrel, and turn them with a parting tool until they are the right contour. Nylon turns very nicely.
I did this for a BMW power window regulator that the nylon washers were no longer available for. Instead of replacing the rivet entirely, I drilled out the peened over portion and mig welded it back up quickly when I put it back together, quenching it in water so the nylon didn't melt. Surprisingly, the BMW mechanism used almost exactly the same track system as the stovebolt system, just with nylon instead of leather.
