The XC70 can tow the same as a V70, at least by rating (in Canada)... And the XC70 holds its value better here too!
You don't see any Volvo's towing around here (well... our 960, but that's about it), but they're probably the only station wagon left around that still have a 3300lbs tow rating (meaning for 1400kg you're still in the clear) - There are no tow ratings on our Passat wagons, Mercedes C/E class wagons, nor the BMWs, Audi's, don't even think the Taurus wagon (POS Ford wagon that a lot of people used to use as a tow car before SUVs became popular) or the new Magnum wagon (think Chrysler 300C wagon- so V8 and rear wheel drive wagon in top level trim, V6 in lower trims) have any real towing capacity either... Leaves you out of luck unless you want an SUV here, or a minivan. I'd rather tow with our Volvo then a minivan any day... Those things tend to be underpowered and overworked on their own anyways.
The XC70 is rated the same as our 960 wagon, 3300lbs... But the XC70 has a much more flexible and stronger torque output - why not tow with it?