I know this is an old thread, but I wanted to leave a note for anyone else that comes along looking for assistance. I had one nylon roller break on the driver's side, dropping the window. Priced the alternatives - found regulators on ebay, etc., for $35, etc. Instead of throwing the whole part away though, I found a fix from someone else (who is ingenious - these forums are worth their weight in gold!) that only costs $1 per roller.
You can use a 5/8" roller (
https://www.google.com/search?q=5/8"+tub+and+shower+roller&ie=utf-8&oe=utf-8), and if you do, the following is not necessary. The HomeDepot I went to didn't have a 5/8" roller, so I used a 3/4" tub & shower roller. I reduced the size slightly on a bench grinder to .675" from .750". Spread the regulator window channel the roller rides in, very very slightly (perhaps .020" or so) using a spacer (piece of 1/4" x 2" x 6" long steel, and a flat prybar, working it along the entire length of the channel). I replaced both stock rollers because I found the other one was already broken in one place.
The window work like new or better, plus, if the nylon roller ever breaks like the stock one did, there is a larger washer on the outside of these tub rollers that wouldn't allow the roller to drop out of the regulator channel and drop the window. I think though, that these rollers will last at least as long as the stock ones - another 17 years! Thank you to ingenious people who post their knowledge to help others like me!