This is interesting. I think that it was established (on the ValiantFans board) that Deathmate Golds were 2 per 100 copies.
The Standard Guide lists the Darker Image #1 Black and White variant as 1/LE (Limited Edition) which would seem to indicate that it is rarer than the Gold.
So if we take the lower number of 1,000,000 and use the same ratio as the Deathmate book (Valiant and Image colluding)... That could mean there are at least 20,000 Darker Image Golds out there. If the LE was more limited (like say 1 out of 100), there could be at least 10,000 copies out there.