If you are looking for performance just check out the Jeep Cherokee with the diesel. In tests it ran with a 3.42 rear and 8 speed and did 0 to 60 in about 8.7 seconds, not much slower than the Ram. The Jeep is not that much lighter than the Ram and the Ram will be available with 3.55 and the 3.92 rear. Haven't seen the 3.21 mentioned but I am sure it will be available, after all it is about mpg's.
On a side note GM announced they will have a diesel available in the Colorado for 2015. You have to wonder how long it will be before GM changes it mind and offers a light duty diesel in the 1500. "The Fast Lane" just did a tow mashup with Ford Eco and Toyota and the Chevy 5.3 was struggling up the hill. It did have a 3.08 rear but the highest option is the 3.42 I believe. So I can't imagine it towing 10,000 pounds up that mountain without killing itself.