Do you need the id based on an item ingame or just without any relevance to the items (I guess so as you wrote "over time unique").
If you have an item relevance you could use:
Lua Code:
GetItemUniqueId(bag, slot)
-- Use this function to get unique hash key for a given id64.
function zo_getSafeId64Key(id)
return Id64ToString(id)
end
http://www.esoui.com/forums/showthre...ghlight=unique