Don't know if I have the same problem as you, but I can relate to irritating noises. I have a strange whine in my new '06
MCSa (2100 miles) which comes on at about 30 mph, doesn't seem to get louder or increase in pitch, and is intermittent at times. It's not tire noise, because I've changed tires and the noise persists. I doubt it's the power train, because shifting into neutral at highway speeds doesn't get rid of it. It could be in the rolling chassis, or some kind of wind noise, but I'm guessing. The dealer couldn't find anything wrong with the car, which is frustrating because I may not be able to live with the noise. I'd hate to have to trade the car because of this, but I have a very low tolerance for squeaks, rattles, and strange noises in new cars. Any ideas or suggestions would be greatly appreciated...