Good question! I had inquired about the Rattus Essen 2011 Bonus Cards since they offered the 2010 cards last year after the fact and got the following response:
We do not have any bonus cards this year, as we are in the middle of a re organization of Z Man games.
We are hoping that the transition will be completed by Spring 2012, and then things will return to normal, and give us more time to do different things.
No sure what that means on the Rattus: Africanus release, but found it interesting none the less...