ItemStack can be serialized/deserialized - We should be able to implement and register our own serialization in a subclass of ItemStack so that we can store extra data against specific item stacks.

We'd need to test how this works with a stack of multiple items? Does it clone() and set the amounts on both, in which case splitting would work fine - not sure about combining together again..

Perhaps it would be best if the extra data was against single item stacks only if there are issues with splitting/combining.

I'm thinking this is more a Bukkit level change, not really suited to clj-minecraft.. So I will create an issue at Bukkit and close this one.

This has been opened here: https://bukkit.atlassian.net/browse/BUKKIT-3124