Back to the OP's question...
I think the differences you'll notice between the 7d and 5d2 are much more prominent in the world of still shooting...While I like the video from my 5d2 a hair more than my 7d, it's almost a wash...Colors are so close, the look at 30p is so similar...I have a tough time telling them apart.
However, for video shooting only, I'm a bit happier with the 7d ergonomically. Not sure if you've handled the two of them...but with the dedicated start/stop button and the level...also a bit better of an LCD and the "Q" quick control, I've found the 7d a bit easier to shoot with in the field.
When it comes to still shooting though, I love my 5d2. I like my 5d for stills more than I prefer the 7d over the 5d for video...so, if I was doing both, I would choose the 5d2. If video was my main concern, the 7d.
Also, to address some of the arguments about moire, and more specifically, aliasing...it is an issue, IF you are not looking to avoid it. You can easily knock chain link fences, shingles, and telephone lines out of focus. These cameras are incredible for people shots and street/candid videography. Faces don't tend to have repeating patterns in their faces...keep your eye out on their clothes though. I've been shooting an HVX200a and original 200 for a couple of years now...and they, too, only resolve around 600 lines of detail...they are also susceptible to moire. My EX-1 "only" resolves about 900 lines...still a couple hundred away from a true 1080 cam...but often, I soften the video...as there is times it can be "too" sharp
There have been plenty of films and videos blown up to 40 foot (and bigger) screens with FAR less resolving power than the current crop of DSLR cameras. They do have limitations...but so does every camera! RED is a revolutionary product. It really is and for us to even be able to compare the two is pretty freakin' cool. The tools available now to the independent filmmaker are incredible! A killer kit can be put together for under 5k these days...and you're shooting high-def!
I'd say the bigger issues many should be concerned with are sound and handling. Picking up an outboard system like the Zoom H4n and a killer tripod/head OR some type of Zacuto/Shoulder/RedRock stabilization system will do wonders for your rig (and can be used with all cameras)...
I respect Barry Green...I own a couple of his books DVX and HVX and several of his DVDs. He and his site (DVXuser) are the reasons I bought a DVX100 and then the HVX family of cams...he's very good at finding the faults in ANY camera and their shortcomings. BUT, if you spend more time reading what he says....he also talks about the extreme value of the 7d at 1700 bucks or the GH1 at 1500 bucks...or even the 5d2 at 2600. We are still in the infancy of DSLR cameras. At this point, these cameras OLPF (Low Pass filter) can only be optimized for ONE or the OTHER...Still or Video. If you optimized for 1080p video, that's only 2 (just over 2) megapixels. You'd be throwing out a hell of a lot of info on the still side with 18 or 21 megapixel stills. These cameras are optimized...at this time...for still, not video. We'll see improvements...just a couple of years ago, mBell is right, the cost was well over $50,000 to get the DOF shots or low light video that this new family of cameras is capable of
They're only going to get better. Nikon (with the D90) and Canon with the 5d2 and 7d....and Panasonic with the GH1...have all hit the bullseye for the video-sumer. Sony has some pretty good history with video as well...My money is on them to join the V-DSLR game too...soon. More competition will breed better products!
J