so how does the focus work on this thing
 

I think I understand that on the 5d in movie mode auto focus is enabled. So is the auto focus smooth and accurate enough for video? if not then it's all manual, but raises the question about holding focus during zoom. so then we have to look for select parafocal lenses.

this is a good all around parafocal lens. It does expand as you zoom though.

Canon EF 24-70mm f/2.8 L USM

any one know of any good range zooms that don't expand as you zoom?

by the way I read at canon that this Wireless File Transmitter WFT-E4A can accept a usb drive as a strorage device. Would this work with the video mode as well?