In Ultima Online when you logged out your character stayed in game for a while, but you could instantly log out in the woods with a bedroll and a campfire. When you started a campfire you had to wait a few seconds out of combat for a message that your camp is secure, then you could use the bedroll to logout. A similar system could work well in DayZ. Maybe just allow instant logout after a short delay at a campfire. Or additionally add sleeping bags. Disconnecting or alt-f4 should leave you standing in game for a minute or two.
