Find me a backpack
The Kata R-103 has a central flap with its own zipper that allows you to get access to the camera without opening the whole bag. The iinside is quiet flexible, and the only disadvantage is that the area for lenses is a bit shallow, so even a relatively short lens has to be put in horizontally rather than vertically.
It has an attachment that will carry a tripod. It also will take a 13" laptop. Kata bags are very well made. They feel a bit stiff at first. I have two of them, a 3N1-10 and an almost unused R103 in perfect condition with all the parts/straps etc. (My gear collection outgrew it.)
E-mail me if you'd like to buy my Kata R-103. My address is visible on my profile.
But in any case, take a careful look at the specs. See http://www.kata-bags.com/product.asp?p_Id=275&Version=Photo