Earlier this year I wanted to create a custom camera mount for use while autocrossing, I could have purchased a similar setup for ~$300, but figured I had the tools and ability to create something myself, so why not do that instead. Below you'll see the results of that effort. For a first pass, using parts I had at the house, I think it turned out pretty well.
This winter I will be working on the next version of this, without using a wood block for the mounting point, and likely a smaller mounting device to attach to the car.
See this mount in action