I agree, Volvos are great, but mostly I've thought of them as an excellent camping rig, but you are right, they can handle a lot.
On my way to meet up with a friend in Moab. I remember it got 22 - 24 MPG with the rooftent on top. It was a luxury 760 RWD with factory positraction and an automatic self leveling system in the back called Nivomat (brilliant).
I loved that car, but I sold it to buy a "serious" expedition rig. Worst mistake I made. Stupid thing, I was getting ready to do a sportsman's showand Hummer sent out a special yellow H1 for me to use. I drove the old Volvo out to pick up the shiny new Hummer at the dealer. After setting up the Hummer I asked the sales manager if it was OK to leave the Volvo with him for a couple days and he said "no". He even went as far as to say "We aren't in the business of selling beat up old Volvos". I couldn't believe it, but I figured I'd better get something more "presentable". Still bothers me to this day, I never should have let being shamed by a Hummer dealer get to me, but it did.
So, now I just bought a 2007 XC70 and am really happy with it. The new 3rd gen AWD system seems to work very well, even though it really is front wheel drive, you can feel the rears kick in. Just added a new sleek carbon fiber Columbus rooftent and am averaging about 24 MPG. Now how can I make it better .........
Rich