I suggest switching to a ~20" polycarbonate wheeled bag. These often weigh about 5.5 lbs, but more importantly will force you to edit slightly what you carry. A smaller person should be able to get quite a lot of clothing into a bag like this. If you can get your netbook and 3+1 into your purse, or sub a larger purse or messenger as your "personal" item, that would help, too. I like the convertible backpack bags myself, but I suspect if you weigh less than 160 lbs and are shorter than 5'6"-5'8" they would become quite unwieldly unless you are disciplined about weight. I weigh about 195 and don't find 20-25 lbs to be a problem in a shoulder bag. I still have wheeled luggage in various sizes. Sometimes it's just the most convenient.