So the mystery of the Stephen Mangan photo from Saturday is solved. He was actually hinting that he's going to be playing Bertie Wooster, nothing to do with DW at all.
Ah. Figured it had to be some kind of tease, since the Beeb didn't appear to be all over him for it.
And...wouldn't it be funny if there was a Spartacus-style wave of every actor who's ever been suggested for the part tweeting pics of themselves draped in an endless scarf, a la Mr. Mangan, just prior to the Christmas special? It would certainly keep people on their toes...