In reply to Urgles:
depends...
Generally bigwall harnesses are the best. Widest and most comfiest around. The Ocun Weebee Quatro or what ever it was, might be just the ticket. That is, you want a harness that is really comfy for both climbing and also for sitting on the rope.
But to be honest, if the sitting on rope is like when you're shunting. More "normal" harnesses are ok (as long as they fit you right). And if the sitting on ropes is like photography or such... well a normal harness and a bosuns chairs would be the thing to get.