He is using portal axles, the center line of the axle is higher than the center line of the hub. They give you extra ground clearance plus a gear reduction at the hub. If you look at Unimogs they have portal axles and there is a company here in the U.S. that builds portal 9" axles but I can't remember who. They are expensive though. That guys project is cool though.

Dennis

95 Sportage, gone but not forgotten.
98 Jeep TJ, 4" Zone springs with RC Long arms, Ford 8.8", 4.56 gears & Detroit locker rear, D30, 4.56 & Detroit Trutrack front.