Would you really include Platinum Games stuff in your list, sin? They had a multi-game contract with Sega, sure, but they're still really more of a third-party, given their largely free reign to release games with whomever they choose. I'm pretty sure they've maintained ownership of all their IP, too.
Edit: NVM, forgot Sega was licensing Bayonetta out to Nintendo. That whole situation is still kind of a o.O