This may be a bit late to answer this question, but I have been running mine without the rear drive shaft for about 3 years, since my move to North Carolina. No problems, steering is lighter, doesn't feel quite as stable on turns when I am trying to act like Schumacher, some increase of fuel mileage and wear is a bit more on front tires (oooh, I love the look people give me when smoke comes out from under the front fenders of my volvo wagon)

good luck

Klaz
v70 awd (sort of)
167k miles
Bad stuff:
-needs second driver's power window switch assembly (until then I'll just deal with three windows working
-Both rear power door lock broken
-needs third A/C evaporator installed
-Cruise control won't work but I'm working on it
-replaced parts include:
-rear wheel bearings
-viscous coupler support bearing ($29 dollars for bearing)
-rear drive shaft support bearing ($43 for bearing)
-parking brake shoes (linings fell off from disuse I guess)
-all front suspension components (lower arms, struts,tie rods, 3rd set of sway bar drag links
-installed an aux transmission cooler which makes the transmission fluid easier to change every 15k miles (symptoms of slipping and buzzing on up shifts)

Good stuff:
most comfortable seats ever made for my backside
runs fast but image is real slow. NO tickets, the invisible car.
Doors still close with a subtle click, feel solid (with all new front suspension components, it had better)