When are they going to announce the next Masterpiece?

Well, I'm getting tired of the endless speculation on whether it'll be Grimlock or Soundwave. Now that the Alternators line is done, this is pretty much the only line that I have any interest in other than the Encore line. And since Skywarp has been released, I'd think they would have announced the next one by now.
So does anybody know when the next one is going to be announced? How were the other MPs announced? Any upcoming Japanese toy shows?
So does anybody know when the next one is going to be announced? How were the other MPs announced? Any upcoming Japanese toy shows?