This isn't really my cup of tea because I guess 1, you can make them all yourself if you have a printer and 2, he sometimes puts in fake cardbacks but there is this seller offering 3-4 pieces of either art/photography/fact file or cardbacks just for display
At the mo he has this : http://cgi.ebay.co.uk/Vintage-Star-Wars-LAST-17-YAK-FACE-PACK-BACKING-CARD_W0QQitemZ200369783930QQcmdZViewItemQQptZUK_ToysGames_ActionFigures_ActionFigures_JN?hash=item2ea6f8447a&_trksid=p3286.c0.m14#ebayphotohosting
There are some nicer images of Yak out there mate, and if you have your own printer you could do some nice pieces just for display