Subaru have done a diesel Legacy for a while that should do an easy 50mpg and does everything else as well as the petrol models. Saying that, I do like the Volvo for some reason as well.
As an alternative, how about a VW Transporter/Caravelle? A mate bought one a few years ago and its proven pretty useful. Heaps of room for people and kit and great for getting changed in or even having lunch if the weather's bad.
His is the 2.5TDI with 180 bhp, does an easy 35mpg and goes like stink. Its got plenty of ground clearance for drifts and with winter tyres is pretty decent in the snow. Surprising nice to drive as well.
Failing that, a Land Cruiser...