How about a Patagonia Half Mass bag with a Crumpler Camera insert? That's what I have, and my ipad fits with ton's of space, so a MacBook Pro might. I have a medium crumpler insert, but I have room on the side and top - so I am guessing a large Crumpler would also fit.
Bonus is that you can use the bag for other things and it doesn't look like a camera bag. The Crumpler has all the pockets and inserts I need.