Partially implemented, but was put on hold as there were bigger issues to look at.

The idea is to have virtual items stored in a stack. An example would be having multiple iron swords, each with a different durability or enchantments that can all be stacked together and used without losing any durability on the rest when one is used or lost.

I'm actually removing this "feature" as it never has worked properly and there is no way to handle all situations as bukkit hasn't implemented most of the new inventory handling. Maybe someday in the future I'll take another stab at this, but for right now, it's just extra code to sort through so it is gone.