I use one of the big lowe packs for my roundshot 70mm camera, which is pretty big. It fits the camera, battery, my roundshot 35(for backup) and still has room for a hasselbald or slr, alond with spots for film. It should be big enough for a 624 camera.
I also have rigged up traditional backpacking packs for larger cameras. One fits my 8" cirkut outfit camera, and another my #6 outfit camera. A regular backpack, some foam, and thin plywood for rigidity, and you have a custom pack for the backcountry
Jamie