Specs: 6.3 V12 with 510 HP.
First AMG model to get it seems to be the upcoming ML63 AMG.
The engine seems also to fit the CLS, the E-class and, hold your breath, the SLK. And of course the SL gets it too.
A bi-turbo charged version may also be in the planning.

The interesting part: the new engine is a 100% AMG development, not a modified Mercedes engine.