Outside-the-box suggestion: have a look at Maxpedition. Their bags are military grade, full of pockets, and covered in webbing from which you can accessorize with other pouches of your choosing. I use some of their smaller bags for 35mm and 120 TLR "run & gun" gear, and also one of their smaller Versipack bags to carry film holders for my Crown Graphic (but I just carry the Graflex by its built-in handle; no need for a bag in my case).