Problem solved, deserves a sticky!

I had this rattle in the b-panel behind my ear when I am stopped at a light that wuz fixin to drive me crazy. Its right around where the seat belt comes out. I just give a little push there and it will stop but as soon as I let up it starts up again.

I pulled the plastic molding back. The only thing holding it on are the top seat belt bolt (used a 1/4" hex wrench on a cheater bar to break it free) and the clothes hook. The other contact surfaces are along the edges of the molding where it fits over the rubber on the frame but the buzzing was more of a plastic-on-plastic sound. There is some dynamat looking stuff glued inside the molding but that is just general soundproofing I think.

Then, bingo. At the bottom of the molding, under the hole where the seat belt comes out, I see a plastic clip with three supporting buttresses. Across from that is a rectangular hole where the clip fits... and just above that hole are three places where the plastic buttresses on the clip have rubbed deep marks into the plastic with each vibration. see pic.

So I stuck a piece of foam insulation on the marks, and as long as I had it out glued a few other pieces around. Buttoned it up and took her our for a test spin. No more BZZ BZZ BZZ.. I love driving again.

edit 3 years later buzzing again. Still, it was quiet for a while..