John Cena vs The Rock will main event Wrestlemania XXVIII
Rumble Winner in Main Event of WrestleMania: 4
SD/Raw Royal Rumble Winner
SD/Raw WrestleMania Main Event (includes two SD star vs. Raw star main events)
This just shows the winner of the Rumble doesn't actually always main-event the biggest show of the year for WWE. It also shows that SmackDown get's shafted plenty of times. SmackDown has only had two main events, while Raw has had a monopoly on them.
It's also obvious the main event of WrestleMania XXVIII this year is Rock vs. John Cena, which is a Raw match. So, no matter who wins the Rumble, they won't main-event.
Another interesting fact is that the WWE championship has not changed hands to a Rumble winner at WrestleMania since 2003.
The only times it changed hands was to John Cena at both WrestleMania 21 and 26. Each year, he didn't win the Rumble, but was the last one eliminated in each Rumble match.
Will the Cena-vs.-Rock match be for the WWE title via Cena possibly winning the title at the Elimination Chamber PPV in February? If that is true, that means the Rumble winner has to be from SmackDown (though technically, a Raw star could challenge for the world title even though that type of thing has only happened twice).
I'd personally prefer Cena/Rock to be non-title, since that match doesn't need to be for the championship. It would also be the first time Cena has wrestled in a non-title match at WrestleMania.
John Cena has been in a world-title match at WrestleMania seven years straight (a record) and eight years straight in any kind of title match since he challenged for the US title at WrestleMania XX.
I hope you enjoyed my little slideshow on the Royal Rumble winners and their matches at WrestleMania.