I disagree with much of the advice given here. The most direct path to your goals, it seems to me, would be the 5D Mk III plus a simple adapter for your Nikon glass.
The dedicated video cameras can't do what a full frame dSLR can do; if you want that cinematic look, then a FF dSLR gives that to you in spades. The dedicated video cameras -- well they look like video. Unless you want to pony up for the high end cameras, such as the C300.
The largest contributor to the "cinematic feel" is a large sensor. The FS 100 has the same sensor-size as film. 3 years ago, you had to go to a DSLR to get large sensor, shallow DOF video. This is no longer the case.
There are a bunch of good comparisons out there. Watch the demo videos and get a feel for what might work for you. Who knows, maybe Canon will blow you mind with their new cinema DSLR. Hopefully that will be announced soon.