Accordingly to this "confidential" diagram, there are six variants of the K-3 III to come. The first one is a deep-black coloured body, the second one is with a modified shutter release button for a different touch, the third one is a monochrome model, the fourth one is a MF model (maybe with a MF focusing screen?), the fifth one is a gun-metal coloured body, and the last one is an astro-model with a modified sensor filter for astro-photography.
Btw, it was also told by Ricoh officially in their recent local marketing event that there will be no new Pentax full frame body in the near future and the K-1 II will still be the current model for the time being.