No doubt you would need to go Ultralight and minimalistic but I think it can be done.
I myself plan on using a Ergon BC3 as well, it'll add 30L of storage and they really are comfortable to wear, doesn't put any weight on your shoulders, the weight is transfered to your hips and it uses a ball joint between your upper body and the pack so you have a full range of mobility.
http://www.ergon-bike.com/en/backpacks/bc3.html