Another small screen villain who's currently sending people behind their sofas, Mads' Hannibal is actually a fairly good template for Lex. His heart is so soaked in evil he'd probably enjoy eating it without gravy - and yet he's able to operate in society, even working with the police to catch people like him.
With Lex surely teaming up with the government in Batman Vs Superman to take down Kal-El, this portrayal would definitely work.
Lex is a symbol for American corporate greed, so Mads would need to work on his accent - a European Luthor might not work as well. We're sure he could pull it off though.