Originally Posted by stewart_photo 
Instead, I suspect a user adjustable feature like this would, at the very least, require substantial changes to the camera's complex built-in operating software. Considering that, and the limited (or no) benefit for most users, it is more likely the company has simply decided that such an addition is not worthwhile in a camera aimed at this market segment at this time.
stewart
No, focus calibration already exists in the debug mode. All that is needed is a firmware update to provide menu interface with reset. Just like the menu interface was adjusted for the additional uses for the thumb wheels. There's already been a long thread in DPreview asking whether this feature would be desirable in the current K10D, and the vast majority was overwhelmingly yes.
Pentax says they are different because they "listen to their customers". This could be an example of that with just a firmware update.
There are various posts around expressing what Pentax explained when they asked them personally for this feature. They feel we just can't handle it like Nikon/Canon owners can.