Hi,
If you have a _shovel ready project_, storyboarded and ready to go, with a crew, cast, budget, etc., then I'd buy the Canon (or rent one - or better yet, hire a guy who owns one as your cinematographer ;-) ) and a converter (Novaflex) for the lenses until the project is done.
DSLR video is a fantastic, but unless you have experience with film making, I'm not sure that jumping into videomaking with a hybrid is going to really be fruitful. It's a long row to hoe.
The real boon to filmmaking that the DSLRs offer is terrific DOF control over cheap (less than $25,000) video cameras, with the opportunity to use some really nice lenses. But the trouble is that to get terrific 'film-like' results from these DSLRs will take more than just pointing and shooting.
There's a lot of hub-bub about the automatic focus on the D7K (and I'm sure it's welcomed by most), but nearly no one that makes film who uses auto focusing unless there's an effect that's he or she is trying to achieve.
I fiddled with my D90 and finally got some nice stuff out of it, but the literature on 'how to do it' is nearly worthless. I'm sure the D7K will be much, much better at doing video, but I'm not so sure the explanation on how to do it will improve at all.
You likely, in most circumstances, could use an APC-S sensor from a D7K with a 35mm at 1.8 or 50mm 1.4, or 85mm at 1.8 or 105 at 2.8 and get the DOF you need for all the shooting for your story. All the DX wides should work (in this case even zooms will work - there shouldn't be any focus or DOF issues - in _most cases_).
There will be additional expenses in monitors, audio devices - I use a Tascam DR100 for capturing audio which means an additional audio guy, microphones, cables, steadying devices, focus pullers, lens hoods, etc., the list will more than double the cost of the body, should you dress the camera out completely - I didn't choose to go that direction, and I have a video component to my business, so some of my investment is already made.
Make sure that you know what you're getting into with the editing software - I teach Adobe Premiere Pro (and Photoshop) as well as Sony Vegas Pro and either of those are easier than Avid.
Most of all, unlike photographs that all have a "place" somewhere - you can always hang photo on a wall - video has to have an audience. You write and produce it _for_ and audience or it has no meaning or basis. You might want to work on your script or treatment first and hammer that out. You might find that your story doesn't even call for a shallow depth of field.
My best,
Mike
