Here’s an apparent picture of Gary’s Medieval Giveaway background, courtesy of Parangaricu2. Apparently a Club Penguin moderator, who is their buddy, was wearing it. As you know, buddy lists show a thumbnail of the playercard and so the background was there, but since it is not released in Club Penguin (or their files that I can access) it did not appear on the actual playercard.
The penguin’s name is Dual Disc. (Thanks Veandito007)