I'm really hoping for at LEAST a 20mpg highway rating. I think that's being fairly realistic. My dad recently bought a 2013 GMC 1500 with the 5.3 flexfuel in it and I don't think he's seeing anything over 16mpg, if that. I'm sure this new diesel will be able to provide better mileage than that. Even if it is only around 20mpg, I don't think the extra cost for the motor will scare vary many people away.
So just to guess, a fairly well equipped version of the new 1500 with the diesel would probably be around $38,000 MSRP, so real hard money, you could probably end up in one for around $32,500 or so. I would definately be sold on one. I'd replace the new 1 ton diesel with an older work truck and buy a new 1500 diesel for cruising.
I can't wait to see more info on the new 1500. Really interested in options and how the 2014 will actually look.