Originally posted by zapp Dream on. If there will be a fullframe Pentax, you do not design it to fit M and K lenses if you want to sell any new gear...
On the contrary, you would - you would just make new K-mount lenses for the body, and update old ones. Just as Nikon did.
A completely new mount has some merit if you're going MILC only, if you have an AF-enabled K adapter, but for DSLR it would make zero sense to create a whole new mount. No current Pentaxian would have any incentive to upgrade to it over a Canon or Nikon FF, for one thing.
EDIT: I see you mean the coupling to fully use older MF K and M. Well, I still think you would sell more bodies that way than you would lose lens sales, and then once you get that buyer into a FF body (vs Canon/Nikon,) you can depend on a yearly onslaught of never-quenchable LBA to keep them buying new lenses. One can only resist temptation so long, no matter how many older lenses you have.