I have two of the f.64 BPX backpacks, one for the 4x5 kit and one for the 8x10.
These packs have a large main section, a smaller section above, and a pouch on the main section cover. It also comes with two removable film holder cases that will each carry six holders. These are very nice, with individual shoulder straps. They attach to the main pack with Velcro, or can be carried separately.
The 4x5 Zone VI fits nicely in the pouch, with 10 lenses, dark cloth, filters/hoods/etc in the main section, and all the meters and other necessary stuff in the top.
The 8x10 Tachihara pretty well fills up the large section of the other bag, with a reducing back in the pouch. I can fit three large lenses + minor stuff in the upper section.