FOUND IT!
My 2008 CVO Ultra has made this noise since Day 1 - and it has been driving me crazy for almost 4 years. I am the first to admit I am overly critical of my bike - but the motor and primary have been torn down 3 times [for other issues] and the source of this aggravating sound was never found.
The noise continued and was VERY pronounced between 2,800 and 3,100 rpm.
Until now......
Replaced my stock windshield with a Klock Werks 8.5" Flare Windshield 10 days ago...
The noise is reduced to the point where most of the time I can't hear it and other times it is just barely noticeable.
Only thing I can figure is that the height and curved shape of the stock shield served to not only reflect this noise directly up and towards the rider - but that the curvature of the stock shield was such that it actually served to AMPLIFY the noise. [much like the shape of a satellite dish serves to concentrate received signals and direct signals gathered over a wide area to a single point, I guess].
AMAZING!
Never would have thunk it - but after 31,000 miles of aggravating me to the point that it actually reduced my riding pleasure..... I NOW have the bike I wanted in the first place!
Of course - there are other HUGE benefits of a Klock Werks Flare windshield, but this one alone made the purchase price of the shield the best money I have ever spent on the bike!
p.s. - I DO NOT work for Klock Werks, so there is no reason whatsoever that I would promote this product other that the fact that it truly worked for me!