[aardvarcus]

I know this isn’t what you want to hear, but…
Depending on what it is exactly that you need to tow, haul, and engage 4wd for, you may be better served with a rough and tough truck with less than stellar mpg and then have a car for those other uses. My first truck I purchased wasn’t up to the task of what I needed it for, and I ended up pouring money into it just to keep it fixed and going. My second truck is up to the task, but it gets very poor mpg. My car however gets halfway decent mpg. My driving is approximately 80% car 20% truck, and with the car at 35 MPG and the truck at 12 MPG, that is the same as if I bought a 25 MPG truck and drove it everywhere. Carrying this forward, if I hit my goal of the car at 40 mpg the truck at 15 mpg and 90%/10% usage, this would be the same as a 34+ mpg truck driven everywhere.
Not trying to dissuade you from getting a truck with good mpg, but I encourage you to first and foremost get a truck that can do/tow/haul/pull what you need it to, and then focus on the mpg and improving it. Otherwise you will spend your time and money fixing instead of eco-modding.


Edit:
Ok, to stop being such a buzz kill, here is my dream MPG/utility truck. Get an old smaller 4wd Toyota pickup (think Hilux/pickup not Tacoma) with the good fully boxed frame. Swap the rear axle out for a fully floating one (GM 14 bolt, some 93+ FJ80s, etc). Put manual hubs on the front if it doesn’t have them. Swap in an overdrive manual transmission if it doesn’t have one (NV4500). Swap in a smaller diesel engine (Cummins 4BT, Isuzu 3.9L, Cummins B3.3, etcetera) with a properly tuned turbo to provide acceptable power and good economy.
If you have time, tools, scrapyard access, luck, and know how you could probably pull this off within your budget.