This is such a great idea!! (Not gonna take it, but somebody has to!) Which would he have to convince Lois of first? What would Lex do to find himself in the K-cage? And if he escaped?
Too many ideas. This has the makings of an epic tale.
Follow up idea: What if Clark decides the best way to out Luthor as the Boss is by remaining as Lex and destroying his whole evil-side-business? And then when Lex (as Superman) inevitably goes rogue, Clark-Luthor has to destroy him?
Probably not in-character, but that's how I like to party.
