i'd recommend anything with a more rigid padding system. your run of the mill bags will have a compartment but often times will have rather thin and flexible padding on the outside. imo, the best solution for a backpack (or any bag for that matter) is something with a compartment that gives u some degree of structural support for your notebook that can help in some way to reduce pressure and torsional stresses to the chassis, particularly from outside of the bag. for example, if u put your notebook in the pouch of a backpack bag, and then have some books in the bag as well, the books are more than likely to be sitting parallel to the computer, so u have a nice even amount of pressure on the laptop. assuming you're smart enough to not lay your backpack on its back so that a stack of books is not sitting on top of your computer, you should be in good shape.
personally, i'd only put a sleeved notebook in a non-laptop bag if it (the sleeve) had some kind of hard shell built into it, which i've seen around. if u get the kind of solution i mentioned in the first place, the need for a sleeve is mostly moot, imo.
one of my current bags is a Dakine and works out quite well.
for the OP, offhand the booq bags might suit your needs.