I propose adding a premium level feature to the Lucy database. Currently when a player who is running Item Collector visits a NPC vendor, Item Collector sees the items in its inventory and updates the database with any new or updated items. If Lucy kept a database of all items on all visited vendors on all servers, premium members could be allowed to search for all items for sale on a particular server. When an item is found, there would be a list of vendors selling it including their names, zones and location.
In addition, a premium user could set up e-mail alerts, up to 10 a day, for any items they are interested in. Imagine I am looking for Words of Abrogation on Stormhammer. I would create an e-mail alert by first searching for items named abrogation, selecting Words of Abrogation, then clicking a link to setup an e-mail alert for that item. I could also click a link in the item info to open a search window. I could then select my server from a menu and click search to list the vendors (if any) that currently have that item.
Of course, the item may not be there if it was sold since the last time the database was updated but at least it would give us a chance to find the items we are looking for. The vendor database should be wiped after every server reset.
This is the kind of feature that would make a lot of players pay for the premium service.