I actually think Momoiro Clover has a shot.
Their major debut single (yes, their first one) hit #3 on the weekly Oricon and #1 on the daily oricon. That's even better than AKB's debut. They have really great members, great music, and their performances are amazing (on the Music Japan female idol special, it was MomoClo's performance that got people talking).
So yeah, I think MomoClo has a shot.