The Matroska 3D support is rapidly growing. Today Syabas Technology, the makers of the PopCorn Hour devices, announced the first hardware support for Matroska 3D files. Mkvtoolnix has better support for handling Matroska 3D (.mk3d) and a the next update will have it completely clean. Finally our mkclean and mkvalidator tools are not completely 3D aware (and Matroska v3 in general).
In other news the specifications are now generated from an XML file. This XML file is also used to generate the semantic data of libmatroska2 (the C version of libmatroska). It could be used to generate other code/document. The generators we use are available in our SVN.