Time to break out the heavy equipment Dave. Go get yourself some good looking metal and start machining. Find a material that would match your existing stand and make your own cable raceway. If it's brushed aluminum (And don't pronounce it Aluminium either, cause it's pronounced Aluminum...no "ini" in it!!!) go get a piece that you could make the same length as your rack is tall, then put holes in at each shelf, make sure to finish the holes in a way that won't harm the cables (like grommets or smooth sanded), then finish the piece nicely so that it matches or compliments your existing rack, put it in the center and invent a way to make it stay there. With the cables out of sight, use any means you want to hold them in place. McMaster-Carr has lots of metals and plastics available to the general public(website too
www.mcmaster.com scroll down to raw materials -> metals or thermoplastics). But with a little finess you could turn a piece of aluminum or stainless tubing or channel into a very nice raceway. And no one would ever know it wasn't part of your rack.