Interior Buzzing Noise

Gerg

My '09 Sport/Touring has developed an increasingly annoying and common rattle. It seems to be coming from the headliner somewhere above the passenger seat, but I swear it sounds like a carpenter bee is stuck up there, trying to escape every couple of seconds. Even worse, is that I can't seem to nail down where exactly the noise is coming from. Since I'm usually driving when I hear it (and I'm almost always the only one in my car) I hesitate to give it my full attention. It doesn't buzz at idle, and it continues when I turn the stereo off, so it's not coming from the speakers.

I dynamatted almost the entire interior trying to rid myself of this problem before, and even wedged down the rear of the headliner to try to get as much of it as I could up there near the antennae, but it's been useless. The sound always returns.

Has anyone else had this problem? Is there a solution that does not involve removing the entire headliner? (I've read that this is somewhat dangerous in terms of the airbags).