Now, I know this is just a 3d-printed lump of plastic, but the details on it tell me it came from a very detailed design file, which indicates serious time spent on the body design. Considering all the engineering that goes into a camera, I'm not freaked out they haven't got a prototype ready for public display- their working models/engineering samples are most likely completely inappropriate for public display (as I would imagine all companies' are- engineering models are probably the true frankensteins of the camera world). So, what this mockup shows us is serious consideration, along with a willingness to say 'yes, we're doing it' as loud and clear as possible.
Even still, this by itself would be slightly questionable, but there are related developments that make this all the more promising. First, the new lenses. You don't release $2,500 lenses of that size,
explicitly stating they cover full 35mm, without having plans for a full 35mm body. Secondly, the K-S2 feels too much like a test-bed camera for new technology: Wifi, NFC, and WR articulated screen. Pentax has shown with the 645d/k5 and 645z/k3 that they will use tech from one camera on another to share costs, so by developing these more minor technologies (compared to the engineering hurdles of full 35mm) in prior cameras they can focus the development efforts of the new camera on the stuff that really matters.
All this tells me that Ricoh does indeed have a deliberate plan and have been making large investments into their imaging division. They're swinging for the fence.
All that being said, please let there be improved AF