Actually, I'm not as confused as you think I am
.
When you use the M42 to K-Mount adapter I agree, the lens sets in the same position bacause the K-mount is larger so the adapter sits flush.
Now the only way that this would work by getting rid of the K-mount and going to the xyz-mount is if the xyz-mount is larger then the K-mount. Then the adapter would sit flush. Pentax does already make a mount that is larger then the K-mount and I admit, I'm am not the smartest person in the world, but I don't think the 645 mount will work very well on a DSLR like a K-5.
Now, if I understand correctly, the Q-mount is smaller then the K-mount. If this is the case then making an adapter that sits flush is not possible. An adapter for this set up would be like using 645 lenses on a DSLR camera. That adapter does not sit in the camera body but on the camera body and does not have any contacts or machancs. In essense an auto lens becomes full manual.
And that is for an adapter that runs almost $200.
Pentax 645 Lens to Pentax 35mm K-Mount Body Adapter 38455 B&H
If I understand correctly, the Q-mount is smaller then the K-mount so if Pentax would use the Q-mount instead of the K-mount, any adapter would be on the camera body and not flush with the camera body, so the adapter would be moving the lens away from the senser. I my be wrong about changing the focal lingth of the lens but the adapter would be like an extension tube and would change the magnification.
And I won't be out of work forever and I still would not want to buy a new body with the xyz-mount if I have to get an adapter to use my current lenses. I think the millions of other people that own Pentax think along the same lines.