Take a look at how the Unimogs were designed. Any time you build a vehicle as a 4wd tractor with the ability to go from a top speed of .09 mph in low low low gear to 46 mph top speed in high gear (20 speed transmission) and a totally sealed (pressurized) driveline to cross streams high enough to put water in your lap (the air intake to the 6 cyl diesel is above the cab), you have a real off road vehicle.
The hill (including side hill operations) climbing ability is legendary.
IMHO that Unimog and its .09 mph would serve better in 4wheeling situations than dual hemis which, i would think, would snap the wheels loose from what ever they happened to be standing on when you hit the gas. Gearing is the big thing.