I've seen many versions of a friction based Follow Focus, most of them designed similar to the IDC FF. Above, is a very early example found at the DVXUser.com forum posted by Ted Ramasola. It's been a good foundation for other ideas, and many people have refined it into their own.
Macro Rail available via Amazon
Using the same idea with Canon Lens rear caps and a skate wheel, it looks like DSLRExperiment.com is busy working on a DIY friction based follow focus with a simple way of mounting camera and adjusting the FF to fit different sized lenses. Using an inexpensive Macro sliding rail for XYZ adjustments and a tweaked metal L bracket, this looks like it could be a simple weekend project. Check out the video below from Vimeo member Mathieu Bujold.
These Macro rails are available via Amazon, but if you're looking for something at half that price, you can locate them via eBay. Here's the style Macro Rail that is used in the video: Macro Focus Rail Slider for Canon Nikon Sony Panasonic