From Sigma's point of view. I personally think Sigma will adapt their HSM lenses to the Pentax SDM mount once Pentax themselves release SDM lenses out in the wild. Sigma *cannot* do a thing until they have lenses on hand to reverse-engineer.
Releasing lenses in Pentax mount is easy, it's the economics at this point that are hard, and again, not to mention the reverse engineering aspect of how Sigma works.
12 months sounds about right. No sign of the two DA* zooms so far, and when they do come out in some days to a month or so (hopefully), Sigma will need time to reverse engineer the SDM protocol that Pentax uses and then manufacture enough stock in Pentax mount to be able to distribute them. I also think they (Sigma et al) are waiting for what Hoya and Pentax end up doing ultimately.
Very frustrating, I know. I've been hoping for some Sigma HSM lenses to come out in Pentax mount as well, namely the 150mm Macro and even the 120-300/2.8. I was lucky I got the DG 70-200/2.8 when I did, seems like the Pentax mount variant is becoming very hard to find. Half our time is spent hunting for lenses... such is the life of a Pentaxer.
Cheers,
-Asad