Well, of course there is no recommendation. The LJ is basically a longer TJ, maybe a tad heavier. They have the same brakes etc, so it's only because of the extra wheelbase it has a higher towing capacity. This is where the weight distributing hitch comes into play, eliminating the tongue dive effect of the load. The average person won't buy one because they are expensive just to increase the towing capacity to 3500 lbs; although it's totally feasible. I was just fishing to see if anyone had done it.
It's not something I would 'recommend' to anyone unless, like myself, they have a lot of towing experience. If I needed to move something with my Jeep (when I get one) this is exactly what I would do. Like Crazyfordiesels pointed out, I would also add ballast to the jeep, and I wouldn't be speeding. I'm mainly looking to pull a small boat and was curious what others had done.