As we have been discussing in other recent threads, there can be a great variation and confusion over what you "proper" torso sizes is. You can't really measure it with a tape measure, thought using the standard method will give you a ballpark figure. This is because companies only give a recommended range, not actual measurements from the pack, because they define that range somewhat arbitrarily, and because people like to wear their packs slightly differently on their body. So just ignore what you think is the right length. You might want to look for a pack that when worn comfortably and loaded the strap attachment at the top are directly horizontal from the tops of your shoulders, and then measure the distance from the bottom or middle (remember which) of the belt to the place where the straps attach to the pack at the top. That is your actual "torso" length, and you can then use that to help find a pack in the future - by measuring yourself. Sorry for the repetition of this point, but it helped me tremendously in untangling the pack fitting knot. Recently I manage to order two packs online that fit me perfectly first time by figuring this out and asking for specific measurements.
Like Jason, I also have weird measurements. I'm short, but have the torso of someone over 6 feet. Basically a penguin. I also have found good-fitting packs with officially designated small, medium and large sizes.