Alrighty, finally I can contribute to the site!!
So I've had this noise coming from the passenger side of the dash for some time now and I've read about it on here. The first response most people would suggest is a washer kit for the hood hinge. Well I just didn't feel like that was the issue. My hood felt fine plus it appears to be tough to get to.
Anyway, started talking the dash apart yesterday. The first thing I did was to remove the glove box door thinking I could remove the shell...nope!!
The shell is glued to the inside of the dash so that's out of the question.
I put it back together. Next, I looked under the dash. To my surprise, only 4 screws held the lower panel in place. This is the panel straight down under the glovebox. There are several heavy wiring harnesses tucked up inside and looked like that was the culprit until I realized that the panel had about an 1 1/2" of foam that the harnesses rested on. So that wasn't the problem either....dang.
As I was preparing to re install the panel, I noticed a 1/4" dia. hard plastic vacuum line or something. It had a small broken piece of electrical tape attached to it. Up above the plastic line was a clip with a small t-shaped bracket. The plastic line originally was taped to the t-bracket. All this time a small 1/4" dia. line has been bumping against the heater duct work. The duct acted like a megaphone increasing the sound of the bump.
I zip tied the tube to the bracket....problem fixed
Later

 

Sweet. Glad you were able to get that sorted out.