Robert-- I'm still trying to get the stomach pouch figured out. A backpack was nice except that the shoulder straps were irritating. My strategy this year is a two-ply basketball jersey from the thrift store- cutting/sewing a pouch between the two layers in the front, removing extra fabric from the back.
Regarding not being able to move with a broken leg, etc.: Yes, that would not fit our strategy very well. I expect that one partner would stay with me, heat water, share parka and sleeping bags, etc., while the other 'Independent Nation' would coordinate help/rescue.