Originally posted by Adam Pentax could be testing the waters with the new K-01, and could be keeping the prospect of a full-frame under consideration. Based on how the mirrorless aps-c k-mount camera does, they could determine whether or not it's worthwhile to make a pro-grade EVF mirrorless full-frame body (and that would pretty much be an industry first).
Mirorless APS-C will sell if it is done with K-mount, but it will not be a race to the "small" form factor. Frankly, in the history of cameras, smaller form factors have not always translated into bigger sales. Canon, Nikon, and Minolta were always tops in sales with the smaller body suppliers of Pentax and especially Olympus in #4 and #5 spots. Tellingly the best-selling Pentax model was the quite large K1000.
So if they can wrestle a K-mount onto a mirrorless as an APS-C alternative and stop trying to make something like Sony NEX's can o' beer and pack o' cigarettes, then there may be something there.
FF is all about market share, sensor prices, and ultimately the shelf price. But I doubt we'd see a mirrorless verso right away for that reason, and also, FF demands a quality OVF, especially with the Limiteds as the marquee profit-making lenses Pentax offers.