"Good news folks! At Photokina you can see the A77 prototype with translucent mirror."
"prototype with a A bayonet : The A -Mount system grows
Sony shows for the first time in Europe, the prototype of a new , advanced system camera with teildurchlässigem mirror ( Translucent Mirror) . The new α model is tailor-made for photo enthusiasts and advanced amateurs, and expands the comprehensive creative possibilities of the previously announced SLT cameras teildurchlässigem mirror ( α55V and α33 ). Unlike conventional digital SLR cameras allow the advertised model extremely fast response time with continuous autofocus for continuous shooting of photos and HD video.
Only the prototype of today was also new accessories for the models of the α series A bayonet presented. In development are currently lightning and a function handle (Portrait handle) and standard zoom and Tele lenses."
http://presscentre.sony.eu/content/detail.aspx?ReleaseID=6220&NewsAreaId=2