Yeah, it was shown by Bostria at Beast of War during the latest Infinity Week. Supposedly the guy who sculpted the model in the end didn't have the courage to put the penguin on the outer side of the briefcase, and so now it's hidden unless you release it.
One of our more talented sculpters took the time to reverse the briefcase, so the penguin is nice and visible.
Yeah I thought it sad to be hidden in the back as well, I found it so funny that I had to instantly show my wife when I found it :P