The storyline will be the Rumble winner will pick his champion to challenge at Maina. Then at No Way Out, we'll see 6 guys go at it and the winner there will take on the challenger that was not selected in the other main event for Mania. Of course who those two challengers will be is still very much up in the air.
If you have listened to John Sefcik and I discuss the topics here or on our podcasts, we have talked about a pair of matches that could make up the mains at Maina that I think would be a decent draw. The first is the obvious one - Undertaker vs Edge. This would involve Edge as the Champion, and likely then Taker winning the Rumble for the second straight year to earn the shot at the belt.
The second main is tough to pinpoint, but I think they would have a great shot at a WM 21 rematch of HHH vs Batista. That would take some doing, but they have teased this twice in the last 6-8 months on TV. It more than likely would mean that HHH would have to be the RAW champion, then Batista would have to win the elimination chamber at No Way Out.
Right now as things stand I think the company is totally not sold on Randy Orton carrying the strap into Mania, and unless he gets things turned around, I feel they will move it before he gets to the big event.