The is a correct answer to this and it was mentioned earlier. The answer is the Mercedes Unimog. Most other trucks are essentially a joke when compared to a Unimog's off-road prowess. On a 1300L you have lockers front and rear, 3 link coil spring suspension front and rear, crawl ratios as low at about 4,500:1, payload of 6,000-8,000 lbs, water fording of 3.5 feet, bullet proof diesel engines, ground clearance of at least 17.5 inches, a very flexible frame and a torsion free bed mount. All that and it is only 85" wide, about the same as a big domestic truck like a Powerwagon. No contest off road.
The only challenge it has as I see it would be a really short wheel base vehicle that is modified like crazy for boulder crawling.