Jensen brought this up in the UFC 76 thread. There really isn't a logically opponent for Rampage now, or Wanderlei for that matter.
Jardine-possibly, but Jardine-Griffin II could happen also too
Henderson-I wouldn't mind seeing it again, but he may be down at Middleweight
Wanderlei-may as well, he may get upset if you give him anyone else
Houston Alexander-looked dominate in 2 performances, but can he fight more than a minute or 2
Lyoto Machida-undefeated w/ non-UFC wins over Franklin and Penn, but not very exciting and main event worthy
Plus Tito/Evans II is tentatively set for UFC 78