They are nearly non exsistant. I go to the yards ALOT & I have never seen one.
What I always tell folks is to get one from a 93- 98 Grand Cherokee. Remove your trailer hitch, if you don't have one its a great time to get & install one, & use the hitch as a guide to redrill the ZJ skid so you can mount it up. If you can find a passenger side nut strip it makes life easier.
I think the ZJ skids are thicker than the XJ..
Don't forget about the t case.