Lets see, to get an angle of view that is more or less the same as the 15mm f/3.5 (the widest rectilinear that Pentax makes for 35mm), they would need to make a 10mm lens. I really have my doubts that this is feasable with the 45 or so mm flange to focal plane distance that the K mount has.
Sigma have already made a full-frame 12-24mm zoom - a 10mm prime sounds tricky but not impossible in my decidedly unexpert opinion :-)
S
