Originally posted by Kunzite 1. I don't like guessing and I have no data on which to make a marginally accurate evaluation; but I'd guess the price difference would be greater than that between the K-50 and K-500.
2. But we know that it's a DSLR, i.e. it has an optical (pentaprism) viewfinder. This is quite obvious in the leaked images:
https://www.pentaxforums.com/content/uploads/files/1/p1344/ks1_pentax4.png
Instead of a shutter (or sensor, if its exposed), we're seeing the standard SLR mirror reflecting the matte screen...
Some people should try to design a working model of this... dream - (almost) the smallest DSLR but with a modular design. Sliding in a stabilized sensor module, on a 120 x 92.5 x 69.5mm body?
Well, with respect to 1. you can easily estimate what additional parts you would need to make a modular cam from let's say a K-x (or whatever). You would need two separate frames, one for the inner cam, one for the outer parts. You would need a mechanical attachment mechanism where the two frames have contact (front of the inner cam, back of the K-mont part). Also you would need limiting walls, one behind the sensor in the inner cam and one limiting the back screen towards the inner cam. The same at the front. Then we would need electronic contacts between the outer parts and the inner cam. This doesn't sound overly complicated. and cannot cost much, considering that you can get a full K-50 for 400 to 500 US$. I do not think this would make the costs leave the entry level sector.
2. Yes, you are right. This looks like the matte screen reflection in the mirror. This seems to contradict modularity - at least of the kind I imagined, which would work so much better with a mirrorless design. Of course, it could be that Uluru is right and just the sensor could be exchanged together with the grip while the rest of the cam, including the mirror box would remain. Yet, I think the main reason for a modular concept would be to allow for a new fully electronic mount while at the same keeping the K-mount for the use of (then) legacy K-mount lenses.
That said, I cannot believe that the gap is nothing but a design feature. Pentax cams have always been designed very functionally and ergonomic (maybe except for the K-01 ;-) ), but this gap would be nothing but a very soon to become ugly dust collector, if it had no other purpose. And, technically speaking, usually it is more difficult to build camera (or other) frames/shells from more parts than from fewer (ask Apple about their notebooks).
Well, the question mark remains...