Yesterday I was given a German army mountain rucksack. Don't know if it's an original or not. Looks nice enough and about the right size for a day out with room for a few extra toys. However. My first thought was, 'It could do with an extra pouch.' Ideally one on the outside sitting between the two straps that run down the outside. Has anyone ever done this? How easy was it? What did you use as an extra pouch (it is tempting to go and buy a similar pack and take off one of the side ones and put that in the middle - but that seems to suddenly make what is a free bag into an expense)? What other mods have people made? Pictures would be gratefully appreciated.