PC Gamer has a story about Everbloom, a toon that leveled all the way to 85 without killing a single mob or completing quests. The leveling was completed by exploring and professions alone.
Now that is some major patience. He started this feat back in November and says:
"Being on the ground and sneaking around mining and herbing and eventually archaeology, going everywhere to get every single point of discovery xp that you can, really gives you a chance to see an amazing world up close and personal".
I can't see myself ever doing this... but I've got to give him major props! I wondered how many times he might have died trying to explore new areas and mine/herb with possibly getting aggro from higher level mobs. His statistics show that he has died only 25 times.