Anyone ever thought of modifying a Prius to make it part-time 4 wheel drive? Most of the time my Prius with snow tires is ok, but it would be great to have it here in Minnesota. Don't want the larger SUV hybrids, just the ability to get power to the rear wheels to get out of snow once in awhile, or not get stuck going up the incline in my own driveway. Maybe wheel hub motors? Only use at slow speeds?