Does a anyone know of a source for the thick (probably 1/4") rubber mat that the Saunders V-Track easels use? It's quite grippy, and doesn't compress too much, considering the weight of those easels.
My wife's a yoga teacher. Yoga mat material is handy as heck - the cheap mats are about 1/4" thick. Some places on-line used to sell it by the foot (she once bought 60 feet of it…)
I found a solution for your problem. My girlfriend found MIV [France] Non-Stick Silicone Baking Liners for $15US at Costco [higher in cooking supply stores like Sur La Table]. Unlike cooking stores which will sell one for $15-20US each, this package has three silicon sheets: