Before you go pulling your door apart check to make sure it's not your glove box door. I tried to find a vibration induced rattle/buzz for months, and then yesterday, while on a bad stretch of road I opened the glove box to see if there was something in it that was rattling. I noticed that the door rattle sounded a lot like the rattle I had been chasing, but different. I put a polishing cloth between the door and the dash and closed the glove box door and the rattle went away. When I got home I put a small felt pad on each flat spot on the door where the rubber bumpers hit, and this was enough to tighten the door and stop the rattle. A slight adjustment to the door catch would accomplish the same thing, but I already had the felt pads handy.
It's worth a shot.