I may have your answer. Here's the situation I had. I painted my calipers last weekend. After everything was put back together, I heard this exact same sound coming from my drivers side. I took the tire off and inspected. Couldn't find anything. After almost pulling my hair out, I had my friend turn the wheel while I was under the Jeep. Here's what you need to look for,
Above your control arm, there is a metal plate. I was trying to find a good spot to put my jack stand. I started jacking the Jeep up from under that control arm. Not a good spot. What it did, it bent the control arm up into that plate. The plate and the control arm were touching and causing friction which is exactly what that sound is.
After inspecting the other side, I saw there was a clear amount of space between that arm and the plate above it. That's what was causing my sound. I bent it back down so the two were no longer touching and the sound is now gone. Mind you, I only tried jacking that one side up before I realized my stupidity.
If you've had your tires rotated or what not, maybe some one decided it would be a good idea to jack the Jeep up from the same place I did. I've attached pictures to help you see how much space you should have. I still have some more work to do on mine. I was in a hurry on my lunch.