After a good submission of info but not knowing your budget limit, maybe take a look at the RAM Ecodiesel. I've had mine for just over 3 years, other than a minor electrical glitch, it runs fine and dirt cheap. Running empty, I can get between 7.5 l/100 in summer and around 9 in winter. If I tow the enclosed cargo trailer with ATV or 16' boat it runs around 10.5. Even towing the 22' travel trailer is pretty good at around 12.5l/100. Ford also has one if you're inclined that brand. GM is "supposed to" come out with a 3.0l Diesel for 1/2 tons but it seems to be stuck somewhere between building them and getting them out to public, not that I would ever buy another GM.