Although I don't see it on the shard list yet, the description of this temporary shard sounds an awful lot like Siege!
http://vboards.stratics.com/uhall/254043-[uo-herald]-shard-dead-dungeon-deathmatch-edition.html
http://vboards.stratics.com/uhall/254043-[uo-herald]-shard-dead-dungeon-deathmatch-edition.html