The only current AWD AMGs are in the ML, G and GL class.
The next one is the rumoured (almost guaranteed) A45 AMG.
I almost sure that MB will eventually come out with some AWD models, simply to counter its opposition, especially Audi in the sedan market and Porsche in the high end sport (read new SLC).
I can envision a C63 an SLK55 TT and maybe an SL63 and SL65.