I have often ranked the 20-30 ranks in chessmasters tower (Fungor (arial assassin) ranked to 36 there as well, killing rooks and knights). After that.. well.. it depends of the group. Organia is pretty decent place to rank from about 30-51 (with 30 meaning that someone else who is of higher level is the tank or there is group utility involved). There are other places too, but these two come to mind first.