http://www.motorauthority.com/blog/1052632_2011-detroit-auto-show-preview-gmc-sierra-all-terrain-hd-concept Ford's Raptor is the undisputed king of production off-road truck awesomeness, but it may soon have a challenger, previewed here with the GMC Sierra All Terrain HD Concept. Bigger, diesel-powered, and suitably brutish, the All Terrain HD is at this point, "strictly a concept," however. According to Lisa Hutchinson, GMC product marketing director, the truck isn't aimed at Baja-style high-speed duty like the Raptor, but rather towing and hauling in harsh offroad environments--it's still a Sierra HD, but with a dirtier side. That's still an impressive mix for a 397-horsepower, 765 pound-foot turbodiesel V-8 capable of towing 13,000 pounds and carrying 2,700 pounds in its bed. The All Terrain HD is able to do all of this thanks to added off-road features including a wider 73-inch track, three more inches of ground clearance, custom suspension control arms, remote-reservoir Fox off-road shocks, electronic front stabilizer bar disconnect, full composite underbody protection, and 35-inch-tall BF Goodrich MK2 mud tires on 20-inch aluminum wheels. As noted earlier, though, you shouldn't get your hopes up: you won't likely be buying one of these, ever. "Although it is strictly a concept, it is a pretty realistic one," said Hutchinson. Hit page two for the full release.