Forget about Maulgar ... 4 off tanks lol ... no way.

Ok what about this guy:

http://www.wowhead.com/?npc=15931

no adds.

This Naxxramas will be a 25 man encounter after WotLK, surely this guy is not "impossible" to 25 box.

This guys is also tank and spank:

http://www.wowhead.com/?npc=16028

This is a stright up fight from all I can see.