Here's how I've been working out the layout of the game for our zombie survival as I've written the script: I think that the story mode won't be too long, maybe 8 or 9 chapters. Survival will be where most people will play. It will be DayZ style, like you said, and the player will find food, water, shelter, etc. Also, the cycles will switch between day and night, and as you play, your count will show of how long you've played over all. I have a couple of questions for your taste:
1): Would you prefer a "simulation" style (think DayZ mod) or would you prefer fast-paced action (think Black Ops)?
2): How would you like the story to play out? Give us your ideas for missions, and we might feature them in the game!