It seems that Amazon France are the first to offer details of the discs, according to bleedingcool.com . They report that the discs contain 2 hours of extras, including a “Making Of” and ten videoblogs, but that no commentaries are listed. The 3D version is split across two Blu-rays whereas the 2D version is on one. Steelbooks with3D lenticular covers are available.
These specifications are obviously for the French version of The Hobbit: An Unexpected Journey but, whilst we wait and see what the US and UK specs bring, I can’t imagine they will be very different.
Amazon France lists the release date as 17 April 2013