Thought I would post a couple photos of the toolholder racks I built for the lathes at work. The first is dead simple, and is just a piece of aluminum angle bolted through a piece of aluminum square tube to the top of the backsplash. The second has more fabrication involved and is a piece of aluminum angle welded to some standoffs to mount on the backsplash of the larger lathe. I added a rack to hold the tailstock accessories and commonly used wrenches.
Both work very well to keep the holders organized and within easy reach. Hope it helps someone!