Soon (being a relative term) we'll have diesel engines in our 1/2 ton trucks. Not just any diesel engine either, the good ol' Cummins name will be on it. They'll be making a v6 and a v8 (I know, I'd rather have an inline too). The timeframe puts it on track to be made around the time the 4th generation Rams are released.

Source: Green Car Congress has the information. Be sure to check out the pdf at the bottom of the post. It lists expected town/highway mileage for the engine in a durango and the 1/2 ton - close to 25 mpg on the highway in a stock 1/2 ton is pretty good if you ask me. Now, the '08 durango is supposed to be getting their new hybrid tranny (yes, the hybrid part is built INTO the tranny) so by the time these engines are on the market I imagine we'll be seeing them in the Ram as well. Add the new diesel to the new tranny and you might have a truck getting over 30 mpg in 2010 with minor mods.