There's a product called Slide-All marketed by Elmer's (as in Elmer's glue...) which consists of microscopic particles of Teflon in an aerosol spray. Once the propellent evaporates, the result is a dry lubricant. Overspray can be a problem, but it wipes up easily as long as it's in an accessible area. I've used it with great success to lubricate Grafmatic holders and occasionally rails on a field camera.