I would hardly say there's a safety issue with removing the rear sway bar. As mentioned on the OEM board (same question), JEEp didn't even have one one the up country package and just imagine the ramifications if it did cause roll-overs, etc. I couldn't even tell the difference when I removed mine. I must not be perceptive enough.
There are many other factors with modified XJ's that could be considered less than perfect as far as safety and handling goes, the removal of the rear sway bar would be at the very bottom of that list.
What's your guess on why no one makes extended rear links/disconnects?