Well some of the exploration quests would actually spawn a mini boss you had to fight in certain areas, so honestly I wouldn't be surprised if they had something at least similar to this. If not, I'm sure they can incorporate it fairly easy. Though to make it really worth it, and create cool exclusive gear like that, it would have to be quests you could only obtain perhaps after you built your allegiance with certain factions up for a while. Still a cool idea.