So, as another update, another day of "field tests" with no solution.
My dealership is in contact and following protocol of a BMW engineer.
Tests include shutting the vehicle off at a higher speed than where the vibration is the greatest and slowing down through the speed, and the vibration still exists.
Now BMW is sending an engineer out to review the problem directly.
I am not sure when this is going to happen but it should be in the next week or so.
My dealership is THE BEST! (Laurel BMW in Westmont, IL) They have been handling this terrifically. My assumption is this is a unique situation and both the dealer and BMW are working towards a resolution, in a timely manor.
But, the Warden isn't too happy
She is getting pretty upset about it all.