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.
|National Gallery of Art by Kukla|
from Your City - Black and White (in colour!)
|Hummingbird and Bee by dibilio57|
from My Best Photo of the Week
|The Snowy Egret by Lee8282|
from Color - Monochrome
|Skate Boarder dpr-0927 by vbuhay|
from Skateboarding Cover shot