[KaVir]

The original poster has explicitly stated that he's looking for a mud with an Avalon/Achaea style combat system (i.e., balance/affliction-based). Both of the suggestions given so far use the standard 'kill' combat system.

Most RPI muds have permadeath, just as most commercial muds use some sort of balance/affliction combat system, but offhand I don't know of any muds that use both. It might be worth taking a look over the list of muds at though.