Take a look at the North Face Surge. It has a laptop compartment, and it looks like any other NF backpack that anybody would use. Nothing about it screams "laptop inside," but it's very well set up (including the other compartments) for transporting a laptop and accessories. There's room for my 17" MBP, even in a Booq sleeve. It's a very effective bag and, as I said, very stealthy.
Is the inside smooth or would I need a sleeve to go with the bag?