I'm a new registrant to this site who took delivery of an Oxford Green M5 in Concord, CA in Jaunary. I learned of this site from the other owners at the M5 Driving Experience in Spartanburg. You may be interested to know that BMW USA does monitor this site "unofficially." I have yet to see another M5 on the road where I live in the foothills between Sacramento and Lake Tahoe.
I'll add you car to the list. You have a rare beast indeed. As you can see from the list there are only a handfull of Oxfords. You should post some pics in the owner's gallery when you get a chance.
As far as NA's "unofficial monitoring" we kinda figured that.