Why have the need for a new guild? Just code up the items and make them a random drop on mobs that you kill. Make the items specific to certain mobs/areas. Why not even mix it up and have it so that you have to "find" an item by searching the area. It could add an rp element and not necessitate the need for coding an entirely new guild and then having to balance them out.

Also, if people are worried about "farming", or constantly killing the same mobs or searching the same area for the item make it a timed drop or a limited drop (ie. drops one per 2 hours or 10 of x ring available in the world at a time).