Thanks for your replies-
After alot of netsurfing, the LowePro Rover might be the ticket but I'll have to
demo it with my gear first. The main problem with most of the smaller 'dual' purpose packs seems to be a inadequate waist belt strap- they're long on the buffed out photo compartments but short on suspension.
With 5 weeks in Patagonia, I want to be set! This time I'm taking my Canon with 1 short zoom and a 1 long zoom in addition to my mainstay Leica m7 w/ 1.4 35mm and Hasselblad xpan, so weight is a factor...
I post back with what I find.