Go for a T4i: Flip out screen very very useful for single operator. Recording cap not so much of an issue.
Look at Beachtek DXA-5Da or DXA-SLR for a way of getting proper microphones into any canon DSLR.
Gives you single files & single unit to hold no synching or forgetting to hit record!
The APS-C cameras have more forgiving depth of field for video (you can still acheive the shallow DoF look) exhibited slightly less jello shutter too.
I have a 5D2, T2i(550D) and XF100 camcorder.
For any work that requires flexibility the APS-C sensor is that bit more manageable. I definitely use the 550D for video more and with the updates now present in the T4i I imagine it is much more user friendly. It is possible that the 5D2 would be too limited if there is much impromptu/fast moving footage required.
I really like the XF100 - the sensor is average - but it has a great codec for edits (especially premiere pro)...but it is not good for stills.
A good tripod is a necessity - I use a Sachtler FSB4 and am really happy with it.
Overall, it comes down to what you really will do the most. 5D2 is great if you want good value with excellent still image quality, but if more than 50% of your use would be video I would look elsewhere.
good luck with it.