a real Unimog would devastate your mooki.
Not quite sure what you're basing that assumption on...but here's the way I see it:
A "real" unimog is special because of its axles. That's it. As far as the 404's go, the engine is underpowered, transmission is weak, brakes don't work well, vehicle is insanely heavy, high COG, 20" wheels limit tire type and size, and a long wheelbase.
I'd like to think I'm taking the best part of a 'mog and placing it under a vehicle that is lighter, lower COG, much better P/W ratio (although less low-end torque), better gearing, better brakes, better steering, lower unsprung weight, MUCH better tires/wheels, better suspension, and shorter WB.
I'd be willing to bet that, obstacle for obstacle, my unimooki would outperform a stock unimog...although I know there are certain times where a long WB and extra weight would give the 'mog the edge. The same goes for any purpose-built rig though...it's only as good as the sum of its parts. Doesn't matter if it is a jeep, zuki, chevy, whatever. It's the parts underneath and how it is designed that is important.