Great idea! Like Brian points out, there are cheaper ways of doing this. A good alternative would be using Unistrut and rollers. A 10′ length of galvanized unistrut is around 20-40$ (in Ontario) and can support a ton of weight, depending on which size of strut you get. There is infinite hardware to be able to build whatever structure you can imagine and if you by brands other than Unistrut, it gets even cheaper and does the same job.