I do not have any specific packs to recommend, because I have not needed a pack that fits your requirements, but one thing struck me right away when I read your post: if a pack must necessarily be long to fit a long torso, but also of limited capacity, then the manufacturer will have to limit its depth and width because they cannot limit its length. Such packs would be fairly simple to pick out visually, because they'll look very tall and narrow.

Sometimes I see packs designed for mountain climbers that have this obviously tall-narrow profile. However, given the stresses on a climbing pack, these packs tend not to be made of lightweight materials and they will include features not useful to backpackers.

You may need to rethink your 45 liter limit on capacity. Limiting your overall pack weight is more important than limiting your pack size. Good luck.