There used to be a time that whenever a Micron Xceed grayscale compatible card came up on ebay, this guy would post a reproduction grayscale adapter for sale.

http://home.earthlink.net/~gamba2/micron_ebay/5114/1268095114.html

If you haven't visited Gamba's page on the card, it has all the info and software you need: http://home.earthlink.net/~gamba2/microngray.html