While we're on the subject of packs, I saw this recreation of the pack frames worn by climbers on the early alpine expeditions in a shop window display. It can't have been too comfortable but it did allow one clever innovation (not included here) where the addition of a drain valve and a fill point (available from any plumbing store) meant that the tubes served double duty as a tank for the liquid fuel of a cooking stove.
More soon
SBW