What makes you say that there are "at least a dozen" armed factions in Libya? All of the rebel forces acknowledge the authority of the NTC and operate under a loose command structure. Different units come from different towns, and cooperate with each other on operations and guard their local areas.
One possible threat is growing in Niger. Qaddafi has a long history of working with (arming, funding etc.) Tuareg tribes and rebel groups in the nations to the south of Libya. In Niger, Tuareg tribesmen who fought for Qaddafi have been returning, freshly armed, and are organizing and threatening to restart their on again, off again struggle against the Niger government. This could definitely spill over into Libya.