watch the vid above for the duck card! its barcode is pretty clearly visible... if this still works I claim the credit for discovery ;P and of course will share that credit for anyone who successfully replicates the duck card that scans under the eye.
It's definitely available. I picked one at some point. I think it was developed for the launch of the game and it doesn't really do anything. It's not usable in combat, just on scan mode as a goof. You can probablly pick one up for about $5.00 if you look around. Search for EOJ Rubber Ducky Promo card.