It's always fun to find out that there's card out there that you didn't know existed, and then try and track it down yourself. In regards to Rickey cards, that doesn't happen to me very often, but it did with the card below.
This card was part of a 2008 team set put out by the Newark Bears, who Rickey played for during parts of the 2003 and 2004 seasons. At the end of the set were a couple of black & white cards that featured famous Newark Bears alumni. I'm not sure how it managed to allude me for the past two years, but I had never even seen one until someone offered to sell me the card in an e-mail about a month or so ago.
The Newark Bears have been on pretty shaky financial grounds the past few years, and were bought out of bankruptcy by new management in 2009. I don't know the print run on the 2008 sets, but I don't believe many of them were produced, and have heard that any remaining sets might have been destroyed when the new management took over.
Here's a list of all of Rickey's other Minor League cards (at least, until another one pops up that I didn't know about):
1977 Modesto A's
1979 Ogden A's
1989 Modesto A's
2003 Atlantic League All-Stars
2003 Newark Bears
2004 Newark Bears
2008 Newark Bears