Sony is said to start production on the PlayStation 4 by the end of the year, according to a report that's come out from Digitimes, which claims that Taiwanese-based manufacturing partners will be readying the new system for a 2012 release.
"Foxconn and Pegatron Technology, assemblers of PS3, will undertake assembly of PS4 as well, the sources pointed out. The planned shipment volume of PS4 in 2012 is at least 20 million units, the sources indicated," states the report. In addition, the PS4 will apparently ship with "body movement-based control like Kinect."
Considering Sony's been adamant about a ten year life cycle for the PS3 and that the PlayStation Vita is scheduled for release by the end of the year/early 2012, this report seems a bit out of whack unless Sony wants to cannibalize their own hardware sales. Take it with a grain of salt.