There's the ring of truth to this. I can imagine it being proposed as a story idea, even if Who already tackled the WWII era in season 1's "The Empty Child". But before too long The Doctor will have met every mover-and-shaker in Earth's history! Still no word on who'll be writing these specials (but expect Russell T. Davies to pen the majority, if not all), or exactly how long they'll be (I'm assuming 60 minutes). Read more here.