Very great job (and happy chrismas)
For translations and categories management, it should be a better idea to use client internal constants:
http://www.wowwiki.com/WoW_Constants (ITEM_BIND_ON_EQUIP, ITEM_SOULBOUND, ITEM_STARTS_QUEST, ITEM_BIND_QUEST, ITEM_RESIST_SINGLE, etc in the hope you understand those choices as exemple ;-) )
an interesting lib that could be used for categories is PeriodicTable-2.0 (ace2 lib) and perhaps (optionnal dep?) TradeskillData.lua from TradeskillInfo (ace2 also)