Well there are a number of vehicles that used rear mounted tanks, believe it or not, the Mercedes G-500 still does, go look under one.
Here are a few more
Older Chevrolet Suburbans
Older S10 Blazers
1st Gen Pathfinders
Older Mitsu Monteros
Ford CV, Mercury full size and All Lincoln Town Cars/Limousine variants.
Like I said all you can do is add the skid and hitch. It would be nice if the safety experts and NHTSA tested this to see if it actually helps. I think it would at least in some accidents but truthfully the rear structure of these Jeeps was not designed for the 50 mph rear impact test, and to expect it to pass that, is not reasonable.
One more thing, the first ZJs with this design were first sold in 1992, thats 21 years ago. The XJ which used a similar design, came out as an 84 model in 83. That's 30 years ago. Yes that long ago. Where were the Center for Auto Safety, NHTSA and even Consumer Reports who tested XJs, ZJs and WJs numerous times and this was never mentioned. I'll tell you what I think, it took a few well publicized accident cases and the safety experts jumped on it, so they could be seen as "doing something about it". When no one was noticing, the accidents were happening then too. I find it interesting that the DOT/NHTSA did not change Federal Safety Standard 301 which has to do with rear impact safety from 1973 (set at 30 mph) until 2008, (set at 50 mph). If they felt this was a problem they surely were not in a hurry to "do something about it".
2007 WK Limited Hemi QDII
1998 ZJ Laredo 4.0 Selectrac