I've received confirmation today, from a very distinguished source at Frogwares Game Development Studio, that a new Sherlock Holmes Adventure is planned to be released at the end of the year.
That Adventure will be entitled 'Testament of Sherlock Holmes', and it will be a full, 3D Adventure game. More information coming soon!
Frogwares have been busy lately and have just released their new Casual game, 'Secret Mission - The Forgotten Island', which can be purchased here; Frogwares
They are also working on a new casual game entitled 'Sherlock Holmes: The Hound of the Baskervilles', and this will be released soon.
Also, a new Sherlock Holmes Adventure for Nintendo DS is on its way very soon.
All can be purchased, either now, or when available, by following the Frogwares link here; Frogwares