I took a small dowel about 36" long and taped a wad of paper towel on the end. I put a liberal amount of silicone lube on it and reached all the way across under the open glass panel, lubing all surfaces that looked like they made contact with non-glass areas. I also lubed the tracks for the glass and shade. It really helped and now I rarely hear anything like the buzzy rattle I used to hear.
UPDATE: While the above helped, it did not fix my problem. I was still getting a plastic-like buzzy rattle around 3,000 rpm and above. Based on what others have said here, I added a layer of rubber shelf liner, the open weave type, over the plastic dust cover with the valley molded into it. Then after that didn't help, I added another layer of liner. It was better, but not fixed. I added a third layer which I wasn't sure the glass would close on it without reopening, but it stayed closed. That helped a lot, but still the rattle/buzz would come back at times. I left it like the for two days to give the layers time to settle in. The rattle/buzz was still there, but better.
This morning I took all three layers out leaving everything as stock. To my surprise, the rattle/buzz was still reduced to far less than I had in the beginning. I'm wondering if the pressure on the plastic dust cover from the rubber layers somehow pushed things down some reducing the noise. The next few days will show if this is going to last or not.
If the problem gets worse again, I may remove the sunroof to get to the plastic dust cover and remove it as suggested in another post. I really don't want to do this, but it looks like dealer fixes aren't working for most people here and I've done the silicone lube thing already.
