At CP+ Show 2013 in Japan, PentaxForums.com interviewed Hiraku Kawauchi and Shigeru Wakashiro, who are from Pentax Ricoh Japan. They confirmed that the full frame Pentax camera is coming.
From CP+ interview clip:
In regard to full-frame cameras, at this point to be honest, even I also thought about whether we should make them or not, but right now I think that we should make them. Even within the company this idea had many opinions on it and some who thought it was a bad idea, but now many people are open to the idea of making full-frame cameras. The development of the technology is advancing and at this point it is being presented.
Small cameras are very important to Pentax, but that’s not what is only unique. Minimizing the cameras is important but having something else is important.