Hey Smudge, is yours an auto or standard? I have an 07 X standard and I have this same vibration. I had someone tell me they had an 07 4 door X standard with the same vibration and it ended up needing a new transmission mount. However, it did take 281 North Jeep (actually Ancira, but now closed-could not happen to a more deserving person) four attempts before they fixed the problem. I took mine to Lonestar and they said it was normal. Now that I have put my lift and tires on, there is no way I can relate to them what it was doing prior to that, so I might be SOL if there is in fact some issue.
I would not take it to Ancira on I10-they have to be the worst service department I have ever had the misfortune of dealing with, hence the renaming of the Ancira dealership on 281 and then the ultimate closing of the dealership-they suck. Renee recommended Lonestar and that is who I took it to this last time, all in all, I was happy. Still a little concerned about the drivetraiin vibration, but it least I have something documented that it was occuring prior to mods.
Keep posting on this. I would like to know if we have the same issue.
Stacy