After the third try, I finally found someone at Courtesy (Steve) who knew what I was looking for. He said they are no longer in the parts book, but he can get them. Apparently you need to know the secret handshake. I don't recall the price, but I don't think they were very expensive. When I get them, I will let you know if they are the right ones.
Jon, You should consider keeping your extra set. If you pull your stub axles occasionally to check or repack bearings the nuts should be repalced at some point. I think the FSM says to use new nuts every time.