What do your tires look like? If everything in your suspension is tight including the track bar, tie rod ends, and jam nuts then I would suspect uneven tire wear from lack of rotation of the tires.

 

I rotate them every 3000 miles....they are Cooper STT Pros.

 

If you can't feel it in your butt it isn't traveling up from the back suspension or drivetrain. Definitely something in the steering/ front suspension/ tires. I wish I could get my hands on it. Diagnosing on the computer is difficult, now I know how the tech assist kids feel.

 

Ok, so the JK has been sitting in the garage, as I have been waiting for a new track bar. Took the old Teraflex one out...the bushings seemed worn.
Put new MetalCloak one in.....test drove. Seems better but still had a slight wiggle at 55mph....then it seemed to disappear. I also noticed that going around a corner to the left, at about that speed, it seems to jig the wheel a little and then wiggle a little again.
I have to wonder if my upper/lower control arms are not set correctly causing the issue. If I remember correctly the angle is 4.2 degrees. I believe I read somewhere that a good point is 4.5 degrees for lifted jks.

Thoughts?

 

I had this problem after experiencing no problems with wobble for a long time.
I have not changed my drive shafts yet and had Cooper STT's, 37's.
After doing everything you've done and whats been suggested, the only fix for me was new tires.
They had some tread left, balanced and aligned.

I now have a new set of Nitto G2's and have not had an issue since. Not sure how old your tires are but uneven tread wear can make the hardened rubber less flexible and make it cause wobble.
When speaking to others with Jeeps that aren't built up, the same thing can happen.

I hope this helps.