DVB-3D HDTV standard?
70hz was mistype, it is 60hz.
Why add a STANDARD if this is not a transmission layer?
This standard already exists: HDMI 1.4/1.4a and it is "frame compatible" with ALL the DTT standards (ISDB-T, ATSC, DVB-T and DTMB) using metadata, because in Brazil (ISDB-T) there is already one 3D channel (REDETV!) broadcasting since june 2010, and also as a south-american channel in a cableTV at Paris, France.
As phase 2, "ability to use one of the two 3D images as a 2D image", this is part of the h.264, called MVC (multiple Video Coding) transparent to old receivers with ALL the DDT standards also.