I hope this isn't adding more noise to the signal: Osprey have a 48L pack that has a 'large range torso adjustable backsystem and hipbelt' (for instance here - http://www.outdoorkit.co.uk/product....tegory_id=1904) that is specifically designed to accomodate a range of sizes as kids grow. This may offer more degrees of freedom in terms of adjustment than conventional packs and is hopefully large enough for the moment... ATB