Update: No joy.
So this morning, before it got too hot (Central Valley heatwave), I covered the steering stem hole with some duct tape in hopes that it could be just as simple as rcannon suggested. (Thanks for the suggestion rc!). Alas, the howling was still there.
It certainly sounds like its coming up from the front more so than the back, but that could be because the sound has nowhere else travel except the through opening at the forks.
Something else I noticed, and this might help you experienced diagnosers, I can detect a hint of the howling noise between 40-44 mph. Same thing with the clutch, as soon as I start to pull the clutch in and get into the grey area or completely pulled in, the sound goes away.
I took two phone videos of the noise. The first vid I just rode up to 78 in 4th gear and demonstrated how pulling in the clutch cuts the sound. The second, I rode up to 78 and demoed the sound in 4th, 5th and 6th gears, and then tried to video from the front of the bike to the rear. Unfortunately for the second vid, the wind noise is too great to really tell.
In the video, the noise doesn't sound so bad, but, from the seat, it is pretty loud.
Now I just need to figure out how to get the video to you all...