Well, I found some answers - that's a Volkswagen W-12 (or WR-12) engine.
it's based on two VR6 engines placed side by side.
The two sides are 72 degrees apart and the cylinders in a given side are 15 degrees apart.
Interestingly the cylinder centerlines are offset from the centerline of the crankshaft by 12.5 mm!

They just came out with a concept putting it into a golf, but is also being used in Touareg, phaeton, bentley and audi.