I made my own headrest mount with some PVC pipe and 2 u-bolts from home depot. I plasti-dipped it all black. Cheap, and it works great, and allows me to mount my phone behind me so that I can see what my hands are doing in the video.
I then use this:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
and this:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
to hold the phone.