On the topic of drop-ins, such as the one pictured in the first post of this thread, my friend and I were thinking of building a similar drop in but with "rollers" (hopefully that makes sence and you can figure out what I mean). Does anyone know if such "rollers" are available to be bought, if so, where we could find some? We looked at Lowes, but they didn't seem to have what we were looking for. Also, we considered the use of pieces of a small-diameter pvc or conduit piping, not sure how well the skis will slide over that though. Any thoughts?