John, this probably doesn't answer you question as such but just for your info, I do use the Ventura Pack but it is held in place by the Corbin Backrest. For me, when I didn't have the Corbin and was using the Ventura rack, I found the thing to be just plain ugly when it didn't have the bag on it. Also imo I don't think the rack could be relied on 100% as a backrest but this of course will be determined by many factors. Anyway here's a photo for you just of the Ventura Bag which by the way with the Hepco and Becker side bags is just a fantastic luggage system, for me anyway.
