What a terrible idea for a TV series. I mean, I don't have any idea on how it could possibly be sustainable.
Don't watch Dexter
I just thought of the perfect guy for Hannibal: Wentworth Miller. He's already played the younger version of a character Anthony Hopkins played as an older man, he's proven he can be the charismatic lead in a TV series, he can do subtle/scary very well, and is currently between series.
For the other guy, oh I dunno. I'd like to see Nick Stahl in something.