OnTooltipSetItem gives a way of hooking all items displayed in a tooltip nomatter how they get displayed vs the current method ColaLight uses of hooking multiple methods of displaying tooltips in GameTooltip and ItemRefTooltip. And it should work with tooltips caused by some other mods that ColaLight currently doesnt work with, AtlasLoot comes to mind as one of them. I could come up with some example code if you want, I'm actually working with it right now for another addon I'm creating.
Ok going to try attaching it to this post. Edit the DumpItemCache.bat to point to your WoW directory and run it to make a new items.lua. If your wondering why I used a schuduled event for the chatframe message, its a lazy hack to not get it filtered by !StopTheSpam.
I've taken the DumpItemCache.exe from http://capnbry.net/wow/ and fixed it to work with WoW 2.0.5 and output using itemids instead of names. With a small addon I wrote to then import any new items and update any items with different sell values, my ColaLight savedvars now has 2417 items in it and growing each day as more items enter my itemcache. I can provide any of these if anybody is interested.