If I were in the market for a new pack I'd look at the following packs first:
Elemental Horizons Kalais (I corresponded with the owner several months ago and they will do custom mods), with the added stays. I'm really impressed with everything I've seen and read about this pack. I'm not going to get it, though, unless my current pack (a 2005 model SMD pack since discontinued) falls apart.
ULA Circuit, although a little heavier than I'd like (it falls within your GF's weight parameters, though)--get the S-shaped straps.
In either case (or with any other cottage manufacturer!), I'd call (or better yet, have your GF call!) and discuss the parameters before ordering. When the pack arrives, she needs to load it up with her gear and the weight/bulk equivalent of several days' food and water and hike around the house with it for a couple of hours. Be prepared to pay return postage if it doesn't work out.