Have to say - no way that Cain would have Rubio as the running mate. I have no doubt at all that that would be too much "minority" for many Americans. Cain was also one of those "conservative" guys otl, and I doubt that would change. You should switch that out for "moderate."
Doesn't really balance the ticket at all, either.
Same goes in some ways for the Dems - Edwards picking Bayh would be quite unlikely.
Someone from the northeast or the west coast for the Dems instead of Bayh, and someone from outside the southeast states for the Repubs. Maybe Jerry Brown or Bill Richardson for the Dems, and Pawlenty for the Reps.