http://www.sigma-photo.co.jp/new/new_topic.php?id=664
(Announcement in Japanese.)
It seems that Sigma, as a 3rd party lens maker (and that Pentax as the least popular DSLR brand), still produces and markets far more exciting new lenses in K-mount than the original maker Pentax herself. The Sigma 35mm F1.4 Art is a really good example, which is even a high-end 135 FF lens but not selling very dear. In fact, Pentax still has no FF DSLR body of any actually. So, this Sigma lens is still a waste when it is mounted on any Pentax APS-C body! :-(
Besides, the HSM motor of Sigma does have far better reputation than the original SDM of Pentax, too! The Saten Super-easy Die Motor is a contemporary shame of Pentax and it pollutes the Star name for the top-of-the-line Pentax lenses which represented excellent quality and reliability for years for decades in the past! >:(