I have an indiSLIDERmini (2-foot camera slider) in perfect working condition (slides smooth as a babies butt). It's a little over a year old, so it does not have the removable puck like the current model.
Here's the specs on the current model:
I'm selling mine for $80 + shipping.
The top puck does not rotate smoothly, this was a "feature" of the original version (as it was explained to me). But if you put a fluid head on it, it's does rotate very smoothly. It came with one 3/8 to 1/4 step up screw, but I'm including a second one in case your fluid head uses 3/8 like mine.