I actually thought the way they used Producer in ep 1 of Idolm@ster was very clever and effective, personally.
As for Cinderella Girls, it's kinda hard for me to get a clear read on stuff at the moment. Only one short pv after all, and in a series where piles of characters are involved....
I do not remember if there has been "official" affirmation for two cour, though. Anyone else happen to have heard something definite?