Don't worry, I haven't heard any news that Sherlock Holmes will be coming to Broadway (or the West End) any time soon...but you never know. At least two Sherlock Holmes musicals have been seen on the New York or London stages in the not-so-distant past.
In 1965, there was the Hal Prince-produced musical Baker Street, which ran for about nine months before closing. The production was reportedly plagued with all kinds of problems, but interestingly enough, featured Tommy Tune and Christopher Walken(!) in their Broadway debuts (both credited as "one of the killers"). Also, Peter Sallis, who would later become famous as the voice of Wallace in the Wallace and Gromit animated films, played Dr. Watson. The plot was loosely based on "A Scandal in Bohemia," adding Professor Moriarty and a ticking time bomb into the mix. I have the CD of the Original Cast Recording, and it's not horrible, although it does come off sounding like a second-rate My Fair Lady. ("And it's so simple, sublimely simple/if you learn not just to see, but to observe/put your brain to work, not just the optic nerve!")
A couple decades later, in 1988, Leslie Bricusse (well known for his writing with Anthony Newley) wrote a musical called--what else?--Sherlock Holmes: the Musical. This musical, which apparently couldn't compete with the other big West End musicals of the day (Phantom of the Opera, Les Miz, etc.) starred Ron Moody, who had played Fagin in Oliver!, as Sherlock Holmes. The plot apparently dealt with a 1901 confrontation between Holmes and Moriarty, and introduces a new character: Bella Spellgrove, the daughter of Professor Moriarty! The show had a limited run in London, and was briefly revived in 1993 with a new cast. According to Wikipedia, "Critical response to the show's original production was largely negative." You can hear a duet between Bella and Holmes from the 1993 revival in the YouTube clip below. It's not too bad...a little slow.
So will Holmes ever return to the musical stage? To be honest, I wouldn't be at all surprised if he did. Stranger things have hit Broadway: trains on roller skates (Starlight Express), Tarzan of the Apes (Disney's Tarzan: the Musical), a murderous barber (Sweeney Todd: the Demon Barber of Fleet Street), and even a murder mystery or two (The Mystery of Edwin Drood and Clue: the Musical). Will we see Elementary or Sherlock become musicals, or something completely unique? Only time will tell...
I'm a stay-at-home dad, and Director of Music Ministries at a United Methodist Church in Mt. Juliet, TN. And a longtime fan of Sherlock Holmes.