OK, I might as well join in the fun of idle speculation...
I will remind you that I have not ever signed an NDA with Pentax or any of its partners
K1000D (the photography class model - a K1000/MZ-5 for the 21st century)
- 10mp APS-C
- No top LCD
- Lightweight plastic body
- shutter speed knob on top of body and single control wheel for aperture, or dual control wheels
- No knob for choosing "program" etc. - simply move the control wheels or shutter knob to go to AV/TV/metered manual
- No built-in flash
K100D Super* (because you can never have enough suffixes or unpronouncable elements in your names - this one at least is pronounce "superstar")
K10D Super*
K2D
Everything else is academic -- a little faster frame rate, a little bigger buffer, higher MP, blah, blah.
To me the key items are these:
Pentax HAD a fullframe DSLR (the MZ-D.) They simply chose not to release it because of the IQ issues. Contax released their camera, and look where it got them...
I don't think you build one fullframe camera and then change your mind that you'll never build another. Pentax hasn't made any big noises about frame size (unlike the 4/3 crew, who try to make their sensor size choice into a plus.)
Pentax continue to list a full slate of FA and FA-J lenses on their website, long after the last 35mm SLR disappeared. Just because you can't buy them in a store doesn't mean that Pentax has thrown in the towel. These designs are current and ready to go... given the need... (like a FF DSLR.)
FF is no longer an exotic non-reality. Pentax could buy off-the-shelf from Sony, from Kodak. So why not? Just to spite your customers? Not every customer will want it -- that's fine, even Nikon know that. Those who do want FF will pay a premium.
Finally, as for the "pentaprism" comment, what I mean is that I expect a new FF DSLR to follow the design cues of the 50th anniversary model that Pentax showed earlier this year. The pentaprism housing is stylish and distinctive -- a perfect way to stand out in a crowd. It's a visual reminder of Pentax's history of innovation. It's old and modern all at once, and would look perfectly at home beside a Spotmatic F, an LX, and a K10D.
(If you think I'm just baiting for a fight with my full-frame comments, I will let you know that full-frame (and 35mm) compatibility is part of what pushed me to buy a Sigma 24-135 instead of a comparable DA/DC lens... I won't be selling my fullframe glass for DA anytime soon.)