Anyway, according to Geek Tyrant, Sir McKellen is set to play an elderly Holmes in an adaption of a book by Mitch Cullen called A Slight Trick of the Mind. Here's the description:
In 1947, Sherlock Holmes, long retired, lives in a sleepy Sussex village with his housekeeper and her amateur-sleuthing son. But far from living out a peaceful retirement, he is haunted by an unsolved case from fifty years ago. He remembers only fragments: a confrontation with an angry husband, a secret bond with his beautiful but unstable wife.Man, Sherlock has certainly exploded back into popularity over the past decade, hasn't he? Two TV shows, two movies (soon to be three, counting this one) and played by three great actors - Benedict Cumberbatch, Robert Downy, Jr., and Jonny Lee Miller. I have to wonder, is this resurgence because the stories and character are entertaining or because they're in the public domain and thus cheaper to adapt and reuse? I'm about 60/40. Hey, I'm a cynic.
With his legendary mental powers on the wane, and without his old sidekick Watson, Holmes is faced with the toughest case of his life - a case that might finally reveal to him the mysteries of the human heart.