Hm, I'd suggest you look into what companies like Helly Hansen, Dakine and such have to offer. They make equipment and clothes for the more adventurous outdoor folks, so you can expect a high price, lots of extra compartments for cameras and stuff, which might not be good if you want to also stuff your laptop into the bag, but the quality of their things is well worth the price.
I'm fairly sure they make waterproof laptop rucksacks too, because nowadays there's alot of adventurers who bring along their computers so they can update their blogs and wahtnot on the move.
Anyways, my two cents.