Maybe i'm late to the party, but i'm just finding this information now or maybe there is a newer (cheaper) version out. Proaim is looking to provide the cheapest electronic follow focus on the market. The Proaim e-Focus Electronic Follow Focus is a wired system (not wireless FF) and comes with two motors in case you need to have control over your zoom and focus rings. A 15mm clamp holds a remote in place, is powered by what looks like Sony NP-F style batteries, and presented in it's own travel bag. Obviously there will be some noise involved with any type of Electronic Follow Focus, and it would be interesting to see how accurate the e-Focus FF system is. I'm sure we'll be hearing more about it in the coming months, so keep your eyes open and let me know if there's some reviews online. You can see them online now via eBay (click here).
Proaim e-Focus Electronic DSLR Follow Focus System