Sureshot: With 3 to 4 inches of travel a properly centered panhard rod(line drawn between the body and axle mount pivot points level) won't move the axle back and forth too much. We run into a problem with the front panhard rod on our XJs
when we lift them. Nobody complains about them at stock height, right?
In the front, for proper bump steer control, the panhard rod has to be parallel to and the same length as the Drag link. For proper suspension movement, the panhard rod should to be about parallel to the body at ride height. Move the panhard rod parallel, we get funky steering, move it parallel to the drag link, we get,... funky steering. Consequently, the panhard rod has a bad rep. in the offroad community.
You're not trying for 15" of travel, so you're not going to run into this problem.
There's another possibility, a watts link.
link to Wikipedia page
I've seen them in racing applications, and (of all things) on mini-trucks.
Biggest problem for your setup is the center link would mount to the dif. cover. It's been done though. Dodge even put one in the Durango, I think.
Personally, I'd go with the panhard rod, just from a mechanical simplicity standpoint. If you're not noticing issues with your front axle/steering/etc, a panhard rod in the rear should be fine.
Don't use the orbit eyes. The side to side flexing in the leaves is controlled/countered by the twist-ability of the leaves, and the hardness of the bushings. The orbit eyes remove the tension from the bushings. They work great for allowing more flex at long suspension travel, but the down side is they loose stability on road. This is the opposite of what you want.
If anything, you might consider solid bushings in your springs. This'll tighten thing up considerably, but you'll get a lot harsher ride, and I don't know about longevity of the bushings or the mounts. I've seen solid bushings in dragsters, but never on an off-road machine. Not sure where to find info,maybe do some research into older rally or dirt track tec. before everyone switched to coil spring/link suspensions.
The YJ had panhard rods because the then "new" spring packs were pretty flexy compared to the older CJ stuff. This was also coming off the end of the Ralph Nader, "You're all going to die in roll-over accidents" bullsh**. A YJ with the panhard rods removed don't handle bad, but they feel a little more wishy-washy the stock.