According to Swedish photography site Fotosidan, they got news from Sony that two A-mount pro DSLR camera will be announced soon. One is 4K camera, another is Fast Full Frame Camera for action & sports photography.
“More cameras on the way On the press meeting Yoshiyuki Nogama told us that a video-targeted system camera with A-mount is on the way/being developed. It shall compete with Canon EOS 5D Mk III and will have Ultra HD video (4K). We guess that this is a continuation of Sony a99. The Sony director also told us that further ahead Sony will launch a really fast full frame camera for action photography,”
In April 2013 at NAB show, Sony already shows their 4K prototype camera, see the image above.