It is a large pack, and depending on the gear(UL/compact), it should have plenty of room for 'up to a week' trips. The question is, will your wife feel comfy with a loaded Pinnacle on her back for up to a week? Some women I know would prefer to carry a pack with a frame when nearing the Pinnacle's largish(for UL'ers)capacity, rather than a frameless model. The majority of that weight is on their shoulders. Maybe a smaller pack for the wife, and you carry the brunt ;) I can't get my girlfriend to join me for longer than one or maaayyyybe two nights, so she carries my modified Golite Ion stuffed with her sleeping bag, pad, light layers, some water, snacks, and whatever else she is willing to put in there beyond that... of course, by then it is stuffed. I carry the rest. I admit that she is a bit of a princess ;) If your wife really wants to carry the lot, and can likely fill a pack as large as the Pinnacle, then maybe she should consider a lightweight framed pack. Granite Gear's Vapor Trail is super comfy when I have 3000+ cubic inches of gear on my back... and I found mine on flea-bay for cheap.
As to the differences between the older model Pinnacle at Sunny Sports... lighter weight and no hip belt pockets. There are other details, but at that price... who cares ;)
Good luck, and enjoy it out there!