View Factor was the first to announce a USB follow focus for Canon HDSLR cameras.  Overcoming the challenges of Canon’s USB focus control has proven to be a huge undertaking.  Their original projection was late summer 2010, but that seems to have been pushed back.

It looks like another person has taken on the endeavor of building a USB follow focus.  They look to be in the manufacturing phase.  Hopefully we will see working model soon.

Read more on Cinema5D’s forums.

[UPDATE] Curt from View Factor contacted us via email with an update to their USB follow focus:

We have been working diligently on our solution and will be announcing more information shortly.