I've been pondering on this topic too.
Double sealing the bag should help to mitigate seal breaks. Toss a small desi pack or 2 in each bag. (Wait for a low humidity day to seal them up.)
Put the bags in an ammo can, and store the can in a cool, dry, place.
I don't see why that wouldn't work for long term storage. The plastic bag edges will take up space, so you'd probably get <1000 per 50cal can. (?)