Rackmount Kit for Mac Pro

We are having our Pro-Tools studios rewired, and need to rackmount all of the Mac Pros in the main technical area. One of them has an old Marathon rackmount kit, but having looked on the web, they don't seem to be around anymore. Does anyone know of a company making Rackmount kits for the Mac Pro. ( We don't want to have to put them on a tray )