The above message is why I endeavored to fix this myself - I don't have time to visit my dealership 3 times for the same problem.
Both my front doors have a rattle - so I attempted a search-and-destroy mission. Here's what I did:
Remove the screws (one inside the door handle housing, the other behind the door pull). Then, starting from the bottom, pry the plastic door facing away from the metal door frame (I started at the bottom outer edge of each door) and pop the white clips out of their holes (some of them will pop out of the plastic door panel instead of coming out of the metal door frame - you'll need to remove them from the door frame and pop them back into the plasic panel before you re-install the panel).
Underneath the outer panel, there's another plastic panel that covers all the interior workings of the door. Before I removed that, I banged on the outer edge of the door to see if I could locate the rattling. It seemed to be coming from the outer edge, somewhat close to the latch. I began removing the bolts that secure the secondary plastic cover, and I banged on the door again - this time, the rattle was gone. I replaced the bolts, and the rattle returned. It turned out that (for my rattle, anyway), the bottom-most outboard bolt was causing the rattle - it must be binding some metal inside the door, causing it to make noise. I'm not sure about the exact cause, but I tightened the bolt, then backed it out about 2 turns, and the rattle has disappeared.
To reinstall the door panel, you have to get it hung on the top lip of the door, being careful not to bend the rubber trim or break it away from the door panel. Make sure to get it hung correctly, or the panel won't fit back on the door correctly. When it's position seems correct, start pushing the white clips back into their holes in the metal door frame. You might have to hit them sharply to get them re-seated. Don't force them, and make sure you line them up before you hit them, or they will distort and will not fit into their holes.
Re-install the two screws and you're done.
