Some possibilities I think are:

Trinidad vs. Vargas
Castillo vs. Corrales, I think this has a lot of probabilities due to Corrales death, and the drama of these fights
Pacman vs Marquez
Chavez vs Randal
Morales vs Barreras
Gatti vs. Ward
Lewis vs. Klitschko

For future series we may have Cotto vs. Judah, Marquez vs. Vazquez