Ive found putting in several NPC's for the same thing (Storage, items, crafting) Reduces lag a lot because of the spread out players instead of all in one area. So I dont think its so much a matter of moving the npc's rather then adding some new ones. Perhaps make a model that is a general storage npc, stone selling npc, so you dont need to come up with new names and art, other then the general one, you know what i mean?
Of course you need to keep the original ones for the quests they are involved with but, other ones to reduce traffic help a lot.
__________________
|