Well, after reading all of your comments, I decided to go out and buy one, so I picked up a Hunter Safety Systems harness from the local Sportsmen's Warehouse. They have several other types, and I can exchange the one I bought if I don't like it after trying it on for a while.
I asked my wife if she wanted to come along shopping with me today, thinking that she would probably say "no" since I don't think there is much in Sportsmen's Warehouse she is interested in. But she said, "sure, and oh, by the way, I have a few other things I would like to pick up while we're out, if you don't mind." Well, she hasn't pestered me about how much this hunting trip is going to cost, so of course I didn't mind, but the bottom line is, this turned out to be a very expensive tree stand harness by the time we got done!