Sony has lately published a filed patent of a CMOS imager with phase matching AF detector built-in:-
Patent details Via Sony Alpha Rumors
So, if this design is to be implemented for a larger sized sensor, say, an APS-C sized one, then this will be really a good news for all those mirrorless system users, e.g., the NEX'!
Previous Related:-
New Technology Breakthrough - Phase Matching AF by Sensor! (Fujifilm's Patent)