Since there are like 8 DayZ maps, they could work in a progression system where you start on Chernarus, and you goal is to get to a boat or plane or something to get to another map. There could be Portal/L4D style clues to point you towards the exit, or to the next clue. So on one map maybe its a boat, another an airfield/helicopter, maybe a car/truck. Maybe you even need to scavenge for items to fix the transportation. Once you get through the maps, you make to some survivor colony, and thats it.
Items are finite, and when a player picks up a weapon and dies, that weapon stays in that spot. Maybe limited spawning of consumable items, but only the basic survival items like knives, matches, hatchets, canteens, etc. Canned food/drinks and ammo should be finite. And high end military items should be very rare. Maybe there are enough ammo for say 1024 players at 3 clips each, and once that number is reached ammo dont respawn on that map.
Maybe once x number of people reach the survivor colony, the server resets. The exits for the maps could be randomized for replayability.
After reading over my post, this sounds a lot like L4D, just evolved to the next level.