"WHERE WERE YOU THREE AND A HALF YEARS AGO WHEN I NEEDED YOU MAN! " -
Thinking up tons of other sage but 'way too late bits of hindsight... :=)
Geronimo - I'm not sure if this link will work, since it's based on a search for "rail" at musician's friend, but give it a try.
http://www.musiciansfriend.com/srs7...28080394180/search/g=rec/detail/base_id/36201
Whether it works or not, they don't give much information. Maybe this will help - Standard EIA 19" rack rails and gear use a spacing of 1.75" per rack space, so a 2-space rail would fit in a 3.5" opening, a 6-space would be 10.5", a 10 space would be 17.5", and so on. The hole spacing is also standard (don't remember exactly what it is though) so any standard rack mount gear will line up with the holes in the rails. The pre-drilled and tapped rails are set up for size 10-32 screws, which are mentioned in the page I linked to. This means a #10 machine screw with 32 threads per inch.
Hope this helps... Steve
Oh, BTW, when building wooden stuff for your studio, I would recommend the heaviest construction you can do, and glue AND screw everything you don't absolutely have to be able to dis-assemble. Light paneling for rear panels is no good. Particle board (MDF) beats plywood, 2x (1.5") beats 1x (3/4"), etc -
Basically, you want mass and low resonance. You'd be amazed at the things that can and WILL rattle in a studio, driving you that little extra distance all the way to INSANE...