As posted before in this thread, I have a TAD Gear Dispatch bag:

Which is 17x12x4 inches (43.2x30.5x10.2cm) big. A great size for my daily commute, as it holds my 15.4" work laptop, a bunch of tools, some paperwork, my lunch and whatever other stuff I decide to lug into the office.
I also have a Fjallraven Vintage Shoulderbag:

Which is 13x11x4.3inches (33x28x11cm) big. I used this to lug my stuff around in my free time, it usually contained my MSI Wind U100 netbook (in a sleeve), laptop PSU, mouse, my Canon Powershot G10, a small first aid kit, a can of deodorant and the flavour of the day in portable audio. (and occasionally clean socks, shirt & underwear, if staying overnight somewhere)
But my netbook died and was replaced with a Samsung Series 9 13.3", While the ultrabook is a LOT thinner, it is a bit bigger in the other directions. Especially when in its Case Logic Welded sleeve ( http://www.caselogic.com/en-US/US/Products/Laptop-Cases/MacBook-Cases/SSMA_-_313_-_BLACK_-__-_13MacBookAirWeldedSleeve ). It still fits the Fjallraven bag, but just barely and as the sides are pushed out a little, there's very little space for anything other than my laptop + PSU & mouse. But the TAD bag is way too big, not to mention that I don't want to be swapping contents all the time. I know myself a little, and I will probably end up missing business-critical items in less than a week time when I need to juggle the work and private stuff around all the time.
So, I'm looking for a replacement. A small-ish messenger bag with either a weatherproof padded 13.3" laptop compartment, or a non-weatherproof non-padded 14" laptop compartment (so it will fit my ultrabook + the caselogic sleeve). And enough space left fo the other stuff. I prefer function & durability over form, and like dark colours best. Oh and preferably something that doesn't scream 'Hey look at this bag! it's guaranteed to contain a high end laptop so please mug me!'.
I keep coming back to the small Timbuk2 laptop Messenger, but they're a bit more than I'd like to spend on a bag right now. So I'd like to see what else there is out there.
Any suggestions?