I use an f64 backpack. It is the large model, about the size of a full scale camping backpack. I carry a variety of gear in it, anything from an 8x10 field camera, to 5x7 field, to a pile of Hassy gear.

I get a few funny looks on short trail outings. I look like I'm ready for a Himalayan assult, but I just don't care what I look like, as long as it gets the job done. I'll be behind the camera anyway.

This may be too large for you, but I know it would do the trick. It has many removable dividers, and could configure to your needs.