So basically, what kind of damage is typical on a camera in cold weather? As a reference point it was 10 degrees F yesterday and the lows can get below zero, but that doesn't mean I'll have my camera out in that weather.
Worst-case, extreme cold will kill the LCD(s) permanently. Double-bag your equipment when coming inside to provide a vapor barrier. Just plunk your cameras in their bags and throw a trash bag over that before you enter a warmer atmosphere (car, house...)