I'm slowly becoming convinced that Del Rio is either going to win the Rumble or be one of the last ones eliminated. It seems to me that WWE is using all this promo time on Raw to get all of the fans (not just Smackdown) used to seeing Del Rio as a main-event level guy, and possibly one of the faces of the company.
I think one of these two things will happen:
1. ADR wins the Rumble, possibly starting a mini-feud with the last person he eliminates to give him more momentum going into Wrestlemania. It's 50/50 whether or not he wins or loses this match, it'll probably depend on how WWE gauges the fans' reactions to him. I'm going win, though. It fits his character.
2. ADR gets eliminated in shocking fashion, setting up a feud with the person who eliminated him that will extend to Wrestlemania, where a win puts him permanently in the title hunt. There are two feuds that I can see happening, and that's either Rey/ADR (perfect way to end the feud, with ADR finally vanquishing his hated rival on the grandest stage of them all), or Christian/ADR (Christian's link with Edge would provide ADR with the stepping-stone he needs to get to the champ).