I see .... I just use my Medium sized North face bag for travelling offshore , 10kgs and there's plenty of room but no extra pockets ! Bloody things bomb proof as its been all over the world but a bit ££££ !
I keep a lookout for the sort of bag you're after and have always failed to find one that matches my requirements in luggage shops. I have two laptop rucksacks that I'm quite happy with. One's a TechAir, the other's a Bizbag - both bought from a street stall on Gt Portland Street, London and each cost £15 or less - admittedly one is 10 years old and the other about 5 years old.
Both are multi-compartment. The Techair has a very well padded laptop section but the Bizbag (the elder of the two) wins, having elastics in the clothing compartment, a second expanding compartment (which, when expanded, causes the bag to exceed the airport sizing box but means that you can get your duty-frees into the bag after you've checked in) and tensioning straps on the sides.
No images of either on the interweb, so save the bother looking. Just pointing out that there's some good stuff in the most unlikely looking places.
Buy a Wenger rucsac and you won't go wrong. I've used mine daily for the past year or so, with a lot of travel in uncomfortable places, and it hasn't aged perceptibly. The strap/bag interface is still complete and the zips are excellent. Cheaper kit will die on you at the wrong time, and this won't. It has all the right spaces for the various bits you carry with you.