Spending several hours in the Nissan dealership when we bought my wife's new Altima last month, I was talking with some of the salesmen about the Nissan trucks. They were all telling me that I should wait until the 2015 models come out (even though I mentioned that I love be Chevy trucks

) They were telling me that the Titan, Armada, and Frontier will all be completely redesigned for the 2015 model year, hopefully by late summer/ early fall 2014. They were going on and on about a Cummins diesel Titan supposed to be like a 3/4 ton truck that will be available for 2015.
They said the Maxima will also be redesigned for 2015. I mentioned hearing about a diesel Frontier on the inter webs, and they said that the only diesel engine they are aware of (so far at least on US models) is on the Titans.