Actually, I've been doing some research into what the original harness might have been, and so far the average price of the harness is between $10-20. I showed some pics of the harness to a buddy of mine who used to be into rescue stuff--he swears that it's an SCBA pack. SCBA--Self Contained Breathing Apparatus. Basically, the pack that holds oxygen tanks for firefighters. And after looking at some pics of newer models of SCBA packs, I think he's right.
General note for everyone though--don't go out and buy an SCBA pack yet! I need to do more research into which model it was, and then I'll pass that info along to everyone. That way, everyone who wants a more accurate harness can get the right version of SCBA pack. Trust me on this one--so far I haven't seen the exact model pack, and some of the pack designs out there are just plain wrong.
So give me some time on this fellow TDHers, and I'll get you that info ASAP. If anyone else has some input on this, please let me know. Thanks!