I went low tech on this and it worked great. I simply used 80 lb test fishing line to suspend the frag racks from drilled dowels that sat against the frame. When I cut the egg crate I left enough room in the front to get my cleaner magnet between the rack and the glass. By drilling the dowels I could adjust the height of the rack by simply adjusting the length of fishing line. A very easy and cheap solution to suspending a frag rack.
Cool... Sounds like a neat trick... should you tie a chalice or an acro to a string off of it you would get some crazy growth patterns... I could see potential.