All the US bound blk/blk M5's came thru the mid-atlantic region of BMWNA. I have spoken to the gentleman from BMW who ordered the cars and he said he ordered between 6 and 10 cars, with black interiors.
I know of 2 other blk/blk US cars, other than mine. One used to be owned by Rob L. of uuc fame and the other belonged to a guy in Chicago.
I have also seen 2 Canadian blk/blk cars.

Rgrds,
David

It is a hot car, no two ways about it. But there must have been more than 6 black on black produced. I don't have any real numbers, but when I have seen 3, 2 of which were up for sale it doesn't seem plausible that I have come across 2/3s of such a rare beast (this one included) given my limited search area.