Anyone know where I may find some ideas to create a "Do it yourself" camera rail system I'm looking to create something quick and in a pinch to hold a follow focus unit I picked up from eBay.

Thanks!

Try in the "Support your camera forum"... Here is a start:

http://www.dvinfo.net/conf/dolly-track-cable/142611-diy-39-slider.html

Oops, just realized you meant support rails.... sorry, nevermind. Probably the section to look in though.

I did see that forum, but wasn't sure it was the appropriate place to post since it seemed like it was for sliders and dollies. I'm looking for ideas on how to build the stationary rails that go under a camera and hold matte box, follow focus, etc.

Thanks!

since you get the mattebox from ebay, continue for the remaining.
look ebay for "universal rod support", there is indian guy selling copy of CAVISION support for about 100$, add the quick release plate for $45 , and you are ready.