They actually built the 6x6 (non portal version) for the ADF and them AMG took one and produced that beast. From memory Styr Puch are responsible for the portal axles but the rest is pretty much standard g-Class equipment 'polished' by AMG.
Ive had a drive in a non portal version and they are quite trick. Very Spartan inside but quite comfortable and relatively capable considering their size. .. If I had the $500,000 plus laying round I would have one
For your viewing pleasure..