A company called Redrock Micro is introducing a DSLR kit to allow for rail mounted lenses and follow focus knobs. At first glance, it looks like a typical rail system, until you notice a 5D Mark II attached. I have to admit, despite my initial skepticism, I'm getting a little more excited to see what people do with a kit like this.
Granted, there are already options on the table to attach 35mm lenses to traditional video cameras, but using a DSLR will make this much more portable (and prevent loss of light through ground glass). I do have to wonder, though. If you're already going through the trouble of using a system like this, why aren't you using a camera that offers more control over and less compression of the image?
// Update: This comment on Gizmodo I think further proves my point that this above the head of average consumers:
How are you supposed to hold the thing other than the handle on top?? The back is just four rods sticking out.
Tripod, dolly, shoulder mount, steadycam, etc. A kit like this isn't meant to be a camcorder.