Tokina employees confirmed that a new Pentax full frame DSLR camera is under development and prototypes already exist. It seems that Pentax also confirmed their full frame DSLR camera plans in an interview with PentaxForums. Rumors about a full frame Pentax DSLR camera has been circulating since 2009.
Update: here is the video clip from the interview with PentaxForums:
Here is the translation/transcript:
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.