Gregory Jade 53

Backcountry.com says:
If weight is your biggest concern after capacity, consider the Gregory Women's Jade 53 Backpack for your long-weekend ridge epic. What this pack gives up in space, it returns in speed, thanks to lightweight construction and ventilated fatigue-fighting FreeFloat Suspension. Gram-counters can easily cram enough gear in this pack for multi-day treks, while casual hikers will find it ideal for overnights and supported trips.