The question is how many people would opt for a V6 diesel in a pickup or SUV when it'd likely be a $2-3K premium? 30mpg is a stretch in a full-size pickup, 23 is more like it. At a 3mpg increase it would take over 100,000 miles to break even on the premium paid. Furthermore, the general (light-use) market still has cold feet about diesels. Where are diesels finding success? In Europe, where gasoline is so expensive, the payback on the diesel premium is much shorter. In the U.S., heavy-duty pickup buyers value the extra low-end torque of diesels. Any gain in efficiency is a bonus. I'd love to see something like a Colorado offered with the rumble and grunt of a diesel, and I'd be one to spend extra money on it... but I'm not sure the overall market reception would make it a good case.