Pentax will use the Sony FF sensor and High Resolution mode.

Image of the Pentax FF prototype at CP+ (Source: DC.watch).

By end of 2015 Pentax will announce their first digital Full Frame DSLR (picture can be seen on top). Rumor has it that Pentax will use the current Sony 36MP sensor used by the Nikon DSLR and Sony A7r. The very important news is that it will feature a High Resolution shooting mode according to the reliable source Thistanaka. The same feature is already used by their brand new K-3II:

The K-3 II is the first camera in the PENTAX line to incorporate Pixel Shift Resolution® for capturing still life subjects with ultra-high resolving power. Pixel shift technology uses the camera’s in-body Shake Reduction mechanism to move the image sensor at single pixel increments, capture 4 separate images, which are subsequently combined into a single high definition image. Benefits include higher resolving power, reduced false color and improved overall image quality of non-moving subjects. 

If Pentax can use Sony sensor and their on sensor stabilization for high-resolution mode…than Sony should do this too! As Diglloyd reported such a feature on the A7rII could generate 144MP raw files of your…cat pictures :)