So, Russian newspaper "Novaya Gazeta" [known for their opposition-minded, anti-Putin stance] have leaked a document today which they allege is a Russian military investigation of the damage sustained by the aircraft.
http://www.novayagazeta.ru/inquests/68332.html (in Russian)
There are two key findings - firstly that the damage was definitely caused by a "Buk-M1" missile (which creates a very specific damage pattern); secondly that the pattern of fragmentation damage suggests that the missile would have had to arrive at a specific angle, from the right and slightly forward and above the aircraft's flight path, and therefore would have been launched from an area further south of the aircraft than some of the previous alleged launch locations. It does not however make any conclusions about who launched it, although it raises many important questions. It does, however, pretty definitively rule out any other weapons that could have been involved, or most of any other launch areas except a relatively small box to the south.
