To expand and clarify my personal crackpot theory:Uchiha Madara lived a long ass time ago, he was a hyuuga but they put the kyuubi in him, kyuubi influenced his eyes into sharingan, he had kids with the same eyes, then they had kids, then they had kids, etc. until you had a clan. At some point he died and kyuubi was either extracted from his corpse or broke free of it.
Basis for corpse extraction:Naruto's seal is if you notice quite unique. Of all the jinchuriki he seems to be the only one who wasn't aware of it until he was told. Why? Kyuubi couldn't just mess with his head on it's own. If you recall he mostly had to go looking for it though there are some instances where he did not. Further Shukaku was sealed in someone else before Gaara a sand priest or something. Also Chiyo mentioned that people have had these beasts sealed in them throughout history but the beasts are all still alive.
Based on this it seems as though a bijuu survives it's jinchuriki though it may be imprisoned in a corpse.