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For the smaller lady? 5'0". A bladder isn't important. It will be used mainly if not soley for bike commuting with a change of clothes, wash kit etc. 10 miles each way if that makes any difference. Not a messenger bag and panniers are not an option so it'll have to be a backpack.
Thanks
My GF's a little taller than you but has the shortest back length I've ever seen. Sh gets on well with the 10 & 15L deuter speedlites.
Am also 5" and have been trying various small rucksacks for the last 30 years! The best fit I've found to date is the OMM rucksacks - I have both the tiny 10l ( http://www.theomm.com/products/packs?page=shop.product_details&flypage=flypage.tpl&product_id=27&category_id=1) and the larger 25l. Both are a great fit re back length and narrow width shoulder straps. Plus they're so lightweight it minimises the total load us smaller people are trying to carry.