I haven't heard anything. I think there was that speculation when Tomlin was hired and he'd convert us over to the 43 (forcing LeBeau out).
But, given the player dynamics and great past 2 years for the D, I personally feel Lebeau can "retire as a Steeler" if he so chooses.
I agree, Tomlin seems like a student of the game, and is loving having LeBeau around. Ive been hearing whispers of tomlin and lebeau working on a hybrid 3-4/cover 2 zone blitz Style, which could be really interesting.