This is my guess as well.....and I'm almost convinced that it will be face vs. face (similar to HBK/Flair).
Two matches that I'm almost certain that will take place include:
-Triple H vs. Shawn Michaels
-Jerishow vs. Edge/Christian
I also believe that we'll John Cena go up either against the Undertaker, Batista, or even The Rock (The Rock is set to host RAW on January 4th and I'd be VERY surprised if we didn't see a Rock/Cena mini-confrontation of sorts).
As far as Taker goes, I'd actually be interested to see him take on Team Legacy (Rhodes and Dibiase) at the same time. Remember - the marks need to be convinced that there's a CHANCE that Taker can see his streak come to an end.
If you're referring to Undertaker's WrestleMania streak (currently 17-0), I respectfully disagree with you. I think 'Taker will retire shortly after WM XXVIII, where he will have amassed a 20-0 record. Besides, a 2-on-1 Handicap match is nothing for 'Taker, even at WrestleMania...let me help remind you of that...