Multi-world inventories

I was thinking of developing a plugin that allows a separate inventory for multiple worlds (so you can run events on one world or have a creative world somewhere and survival on another). So I have a few questions (as I'm relatively new to OOP):

1) Is anyone else working on this or has it been released and I can't find it?
2) What is the best way to story an array of Itemstacks (inventory)? Serialization?
3) Should I use a database or flat-file first (probably support both in the end)

And any suggestions?

Edit: I can't find a change world event so... this is on hold until I think of a way to fix that.

Edit 2: Teleport event may work... looking into it.

 

Any hope of this happening? was looking for a plugin to do this today, we are looking to have a world that people cannot take items over to.

 

You could look at this plugin: http://forums.bukkit.org/threads/mech-multiinv-v1-4-0b-per-world-inventories-440.4742/

About teleporting to other world

Code:

player.teleportTo(getServer().getWorld("worldName").getSpawnLocation());

 

Perfect, thanks exactly what I was looking for.