XOC members "Huey", "XSAL", and "johnnyx" have them. "CharlieX" may have them as well. All are in the Nor Cal area and I think each of them drove to Sacromento to meet Roger and pick up the sliders. (saved on shipping hassles;) Roger even helped them to install it, on the spot.

Those are my first choice as well, based on the reasons listed previously. They seem to be a good compromise on cost, quality, and design. I hear the others in NCCX have used them and they survived a pretty good beating on the trails.