Welcome to the forums.

Some brand names to investigate including the two mentioned are Kata, Crumpler, Lowepro, think tank. and tamrac. I ended up with a Lowepro Fastpack 350 and it may do exactly what you are looking for. Actually, you may be able to get away with the Fastpack 250. But I was also looking into the Kata 467i and Kata Bumblebee.