Take a look at what I did about 1/2 way down this thread:
post6077097.html?hilit=ncline#p6077097
I used some rollers from a ford thunderbird I think and I got them for like 3.95 each or so from Florida Auto trim. the "rollers" were the easy part. grind off the old studs put the new ones through and "musharoom" them over like the original but with a hammer. the hard part was creating the guides from scratch.
I did this last year and haven't had any problems with them at all.
If you want a write up let me know, I took a lot of pictures but they are kind of blurry.
If you want the part numbers that I got from Florida Auto trim let me know as well.
Nathan