General Motors has reportedly cancel plans for a new unibody mid-sized pickup truck after finding it wouldn't get much better fuel economy than existing body-on-frame designs. In early 2008, GM showed off the GMC Denali XT concept at the Chicago Auto Show. That truck was actually based on the same Zeta rear wheel drive platform used for the Pontiac G8. And unlike the star-crossed G8 ST that never made it into showrooms, the intended production truck would have been derived front-wheel drive/all-wheel drive Epsilon II architecture like Honda's Ridgeline.
GM vice-chairman Tom Stephens told Automotive News the unibody design would not give much of an efficiency boost while losing capability that buyers were willing to pay a premium for. That means the trucks would have been less profitable, something GM is obviously trying to avoid. The current four-wheel drive Chevrolet Silverado pickup has an EPA rating of 14/20 mpg while the all-wheel drive Ridgeline only gets 15/20 mpg, so there's clearly something to this.
As a mid-sized truck, the unibody would have likely replaced the Chevy Colorado/GMC Canyon, two vehicles that are getting long-in-the-tooth. It's not clear how GM plans to handle those products (or that segment) going forward.