It seems like Bilstein (according to their online catalogue) are in the process of developing B6 Sport shocks for the rear of the 2012 M Class and B6 Heavy Duty for the fronts. I am really interested to see if they will fit the WK2 also. I can't find any literature that clearly states what suspension parts if any the WK2 and the new M Class share, but a lot of people are saying they look the same (which means nothing until someone fits them though). I guess we'll just have to wait until they are released.
Resurrecting an old thread here, but it seems Bilstein has just released their shocks for the 2011+ M Class, but at 289 Euro each ( plus Shipping + Fitment), it might be a while before I can sneak this purchase past the wife and test the fitment on the Jeep.