I'd use something like this: http://www.normancamera.com/LOWEPRO-...FILM-DROP.html

You could even use the same bag exposed and unexposed film by just making sure all of your exposed film is fully rewound into the canister. Alternatively you could throw the exposed film into something else. A shotgun style belt or vest will just end up looking goofy and antiquated in my opinion. Also, as others have mentioned, for color, I would consider sticking to just 400H and perhaps a few backup rolls of 800Z. However, for black and white I would make sure you have some high speed film on-hand - either TMZ or Neopan 1600 would do.

2 bodies should be a given.