Re: question for the some of the jeep know it alls!
After 30 min of driving go back to your house, put a jack under the rear pumpkin (differential), jack it up and turn both the rear wheels. If you think it is coming from the right rear, then it just might be a bad rear bearing.
Compare the left side to the right side.
I presonally think that 30 min is about the right amount of time for the wheel bearing to warm up and start showing the problem.
While your at it, with the trany in neutral, turn the drive shaft and make sure all it ok. Bad u-joints can usually be felt this way.
BTW...if you don't have a good hydraulic floor jack....go buy one. It will pay for itself quickly.