As far as I can remember in the past the UFC has created interim champs in a completely redundant fashion. They've been number 1 contender fights, not interim belt fights. The two that spring to mind are Carwin-Mir and Condit-Diaz. For the Carwin-Mir fight I think it was decided before the fight that the winner would face Brock. Condit-Diaz - UFC let Condit sit out donkeys years for GSP instead of keeping the division ticking over like an interim belt should. With Barao as interim champ there's been some interesting match ups that have kept the division active. Now when Cruz comes back there should be a great match up waiting.