Maybe the CX-5 diesel when it comes out...the tow rating with the 4 cylinder is only 2000lbs so rather puny, but I'm hoping with the diesel they will up the tow rating.
The Volvo V70's were always great wagons with good tow capability..3500 lbs rated, could probably even do a little more. T5's can get 30 on the highway. They don't seem to be making those new anymore, though. The V50 is only rated for 2000 lbs, unfortunately.