Pentaxians might complain about why Metabones didn't make their "Speed Booster" in K-mount? I think it is just a market(ing) decision after all.
Still, if you want to get something similar to use, i.e., to put your old Pentax FF lenses onto the current APS-C cropped body, here is an alternative solution:-
http://www.sonyalpharumors.com/
