I think Nissan is looking at following GM's lead with a Diesel in the Frontier; might want to look at that, but it is a year or two away. I commute from Conifer into Denver everyday, and 16-20mpg is not fun; hopefully, the Frontier is better then 20mpg. The diesel in my Jeep helps a great deal with fuel economy as well as performance in the mountains.
Although, I have never understood the purpose of a mid size truck. The box is too small to do much of anything; why not just get an SUV so you have the flexibility with cargo and passengers? What does the small box really give you? ...except the need to purchase a utility box or topper...or both. However, I don't understand the purpose of the ½ ton pickup either; why have a box unless you can put 5,000lbs of rock in it, or the flexibility to do any job. I don't agree with the suggestion of getting a ½ ton as a commuter in the mountains; what a waste of gas and money.