A director that I've shot 6 features for, Michael Polish, has recently shot two features by himself on a 5D and the first was sold thru iTunes, "For Lovers Only" -- it looks quite good. Personally, though, DSLR-video's main attraction is the cost, I don't feel a stripped-down Epic is much larger or bulkier... and it's a lot more friendly for shooting dramas on. I'd even prefer using a Sony F3 or Canon C300 or now C500... But that's speaking as a cinematographer, not a director/cameraman/editor who is going to make a whole feature by himself on his own dime and cut it on FCP.
In my world, using a still camera to shoot HD video is more likely to happen as some sort of crash-camera, or some other situation where you have a tiny space or want to sneak a camera into some place like a subway, etc. -- not as the A-camera on a feature. But if wanted to make a feature on my own dime and spend under $10,000 total on the camera package, then I might look at DSLR's (though to be honest, I'd be more likely to borrow something...)
We are all aware by now of the artifacts of a compressed 8-bit 4:2:0 or 4:2:2 h.264 recording, the aliasing and jello-cam issues, the dynamic range limitations, etc. But certainly some nice work has been done with these cameras despite these limitations. But personally, I'd rather shoot with something that is at least 10-bit Log 4:4:4.