[Shostak]

I like the idea (or maybe just my memory of the idea) of the Cauldron Born from The Chronicles of Prydain, which lost strength when straying too far from where they were "born." This way you can have zombies guarding tombs for centuries or a whole division of them protecting a necromancer's stronghold without need for maintaining them with rings. I also like the fact that they were by no means "lesser" undead; to stop them.