My family supported Mr. Cain in his run for the Senate. In fact, we passed by his RV going down the Interstate and exchanged honks.
Mr. Cain discovered he had cancer in 2005. His service in the Senate might have been brief, since he would have been forced to resign.
He might have challenged Saxby Chambliss in 2008 in a Primary Fight, but I guess we'll never know.
I like Cain; but I don't think he would've done so well in 2012, though as you said we'll never know. People liked him for his ideas and the threat he posed to the establishment: never in elected office catapulted to frontrunner.