3k is easily recouped when the truck is a DD. The difference between 15 mpg on DD duty and 25 MPG is fairly significant. Plus, diesel is the price of premium fuel down here so I don't see the big difference in price. A 3/4 ton is too large for my applications and finding a 5.9 that hasn't been chopped up by a redneck is impossible/expensive.
The next gen diesels in 1/2 tons are going to be the 5.0L Cummins. 300 HP and 500 TQ is not going to get above 25 MPG on the highway either. Too big of an engine to be a fuel efficient & if it isn't FE you wine as well get a 3/4 ton. The only thing that will force Chevy or Ford to get in the diesel game is if Dodge makes a killing on this EcoDiesel, which in the first month 8,000 orders flooded the market and they can't keep up with the demand (they being VM who builds the engine).
Plus, real world application of the 3.5L ecoboost hasn't proved IMO that it saves gas at all during towing (
http://www.fuelly.com/car/ford/f-150/gas%20v6/truck). I think Ram hit the balance well and is the reason why I'm considering. Plus the interiors on the trucks (all top line models in every brand except Nissan) are pretty top notch.