I actually have a factory cross bar to hold up the spare tire on one of my MJ's. I can get a pic if anybody is interested. It came on a nice stock 2 wheeler I bought.
Are you going to use it? Are you interested in selling it?
I'm going to do a full restore, and honestly I've never seen a crossbar for the spare. If I'm gonna do this all correct it's one of those bits that would be awesome.