Originally posted by feishui If Ricoh wants to make the new pentax mirrorless successful, they must somehow take advantage of the existing limited primes, rather than make any new adapter or new lens recently
Not going to happen. The primes were designed for a long register distance. To get that distance you need an adapter which will neither be small nor inexpensive. Once you go down that path, a manufacturer is actually better off making two camera bodies for different lenses than one body for multiple types of lenses.
A collapsible in-body adapter frankly, is silly. It would have to be so thick it would rival in dimensions the register distance existing already in the DSLRs. Have you ever used an FA*24 on a K-x? For that glass (and many others) you need some physically large structure to support the optics. This is one of the design reasons why the SLR became the dominant upper-end form factor for cameras: the mirror box needed room and that room could be dual-purpose for large glass mounts. SLR's became the telephoto masters as a result.
The whole point of mirrorless is NOT to make the body smaller per se. It's to make the whole system smaller. That includes the optics. So if you go mirrorless, by definition you're moving from the SLR k-mount to a new mount entirely.
My sense from the Ricoh announcement is that they'll be doing their version of e-mount. APS-C to start, FF when (if) sensor supply gets to the right place. K-mount was not mention, so assume the status quo, albeit with much slower development.