Currently, I am using a tenba small messenger bag. I put 4 lenses (28, 18-55, 55-250, 10-22), all my accessories, can put a laptop in it, hd, documents, etc. it doesn't have something to attach a tripod to though.. It is very well made, water resistant material, love the zippers and I really like the removable camera/ lens pouch. Fully convertible. I have carried/shouldered the bag almost all day and it can get to you since the weight is on one side. The top zipper is very useful to get your gear quickly and without attracting too much attention.
I have a 100D/SL1, which is a tiny dslr.. The bag makes the camera even smaller in a way.
for an attached bg on a 5m3 w/ 70-200. The large messenger bag should do justice. I recommend this bag.. Had it for about 4 months now and traveled to Korea with it so far. Very nice to put your documents like passports, tickets, maps, and other things in it as well. Again, we're always looking for that bag to fit our preferences so happy hunting.