Woops, I hit "reply" instead of "reply group".
What you are looking for is commonly referred to as "relay rack rail" or
Not cheap stuff!
You might also find it at one of those high-end entertainment systems
dealers or installers.
If you have the time, a good drill press and enjoy using a tap, get some
angle iron and make your own. Use the dimensions found here:
Make sure you get those measurements right. It is a real PITA to try to
install gear in a rack that is built up wrong.
If you know someone down at the phone company or cellular company, they
might be able use put you in touch with some old racks being replaced. I've
been in warehouses full of that stuff. I guess it has to be stored for a
number of years before someone gives the ok to call a recycling truck to
haul it of to the scrap heap. Nothing wrong with most of it. Just the
wrong style/brand whatever. With all the mergers and acquisitions,
sometimes stuff is replaced just to standardize the gear used. For that
matter, check your local scrap metal dealer. He may have a pile of it.