NOT MINE : but I noticed a couple of interesting cards at reasonable BIN prices from this seller on the Bay
also has an IBM mono card
http://www.ebay.com/itm/256KB-Memory-Card-Generic-1-2-of-memory-installed-For-IBM-PC-XT-Clones-/111013082674?pt=US_Vintage_Computing_Parts_Accessories&hash=item19d8e53632
also has an IBM mono card
http://www.ebay.com/itm/256KB-Memory-Card-Generic-1-2-of-memory-installed-For-IBM-PC-XT-Clones-/111013082674?pt=US_Vintage_Computing_Parts_Accessories&hash=item19d8e53632