Before I start, I just have to say: Based on the treatment I was shown at Panasonic today, I may just be a Panasonic customer for life!
I recently purchased the 42PWD4U after FedEx broke my Sony PFM 42B1. I worked with Crazy Eddie in NJ after being wary of shipping these things across the nation, and got the unit the same day I placed the order. I told the salespeople I did not want a "buzzing unit," they assured me it would not buzz. Nevertheless, when everything was plugged in, BUZZZZ!!! LOUD! When I called back to get support for the buzz, they said they would call back but never did. I would not recommend buying from them again.
On to the good stuff. So I called Panasonic in Secaucus, NJ, and spoke to the head of the Broadcast Engineering Center. They service units for the likes of NBC, ABC, etc. Alex, a very nice man, he directed me to the Secaucus campus, right off the Meadowlands Pkwy. Needless to say, I rented a car and went there today. Arrived early in the morning, and then watched the crew work on my unit.
The buzzing apparently comes from some SMT capacitors that cause a piezoelectric effect. The new units (OCT 2001) have the new capacitors installed on the line, but are not in the country yet. The service notice is dated 9/20, and details the replacement of the SS and SC boards, which apparently now have low piezoelectric effect ceramic capacitors.
After replacing the two scan boards that have the "high piezoelectric effect capacitors", the buzzing was significantly lower! The unit is not silent, but it is more of a ZZZZ now, instead of the higher pitched BUZZZ of before. The actual volume of the ZZZ is also much lower.
I can now watch the Panny in peace -- Hardly hear the noise now, although if you try to notice it, you will still hear the humm.
I had the chance to meet Alex, Bob, and Peter -- they were extremely helpful and really accomodating. If anyone here has a a chance to visit, I think you will be impressed with their professionalism and hospitable disposition. If you guys are out there: THANK YOU!
I mentioned that once news reached the public about this, the line would be out the door. They didn't seem to mind

.
So for those in the NY Metro area, looks like you may be able to get your unit serviced in person. They noted that I was one of the first people to receive the fix, so I'm not sure what their scheduling is.
To protect the staff at Panasonic, if you would like to receive contact information, leave me a private message here, and I can email you the number.
Once again, I could not believe how quick and effective the solution turned out to be. And for those of you waiting on the Dell units, I assume you will be receiving the updated capacitors and won't get a super loud BUZZ, just the now soothing HUMM.