Good roleplayers create conflict when they want it to happen.
Good roleplayers also understand that even in their idealized fictional worlds, there will still be times when they/their characters don't get what they want all the time, and just keep playing towards their goal anyway.
PlaneShift has good roleplayers, and if you're lucky enough to find them, you'll have in-character conflict up to yer eyeballs.
Even something as simple as an NPC quest can create conflict. I just had the best roleplay session ever with two other players merely discussing a quest (and our backstories as well, but the best parts had to do with the quest).
EDIT: Oh, and for the whole dark fantasy thing? It seems like regular fantasy to me. Dark at times, and utterly lighthearted and silly at others, just like real life (but with Elves and Magic and Ulbernauts and suchlike ;P).