There's one in the R15 main scenario quest. It was fun because I wiped the first time, but then figured out how to defeat it. Be sure to set your aetheryte return point in the city before starting the quest.
I think I remember reading that in either the Nov/Dec update, they'd be introducing some "rare" type mobs. I also think there are some tough targets in the R30 regional leves.
Djigga, please. Highland Hyurs can't jump.