Pioneer Electronics recently came out with a new head rest mount monitor (AVD-W6200) that has a really nice mount. if you take the monitor off of the mount and turn the head of the mount 90deg, it makes a perfect camcorder mount. It doesn't just clamp to the posts, it actually attaches to the seat mounts that the posts slide into, so the headrest is still adjustable. It also comes with a quick-release foot. It will only mount to the driver side, but it sees around the driver just fine. It will fit any adjustable headrest with a post spacing from 4 3/4" to 11 5/8" apart. (sorry EF civic DX guys, your posts are too narrow)

I have contacted Our Rep at Pioneer and asked if the bracket is available without the monitor, and he said not yet, but he'd let me know when it is. In the mean time, a lot of stereo shops are ordering these monitors and flush mounting them, so they may have some extra brackets lying around.

Here's some pics of the bracket mounted in an '02 Subaru WRX:

 

Very nice... probably a little more expensive than the common DIY, but it sher is perty.