Does this mean you can put away your Lego Bilbo Baggins and Kre-O "Mystery Villain" from Star Trek, and finally get a Sherlock and Watson that are in scale? Not so fast. Fan support doesn't necessarily mean Lego will either approve of the idea or get the rights.
Timely-Tardis-Lego, who sent in the tip, suspects the show's content is too dark for Lego's family friendly image, but I suspect the set as pitched is simply too non-dynamic. Make it a villain chase and you have potential, but just a living room diorama, with no action features...I don't see any toy company going there, to be honest.
Now, that terrible rip-off Lego that has the Doctor Who rights? Maybe you should hit them up - they could use another license.