A new patent for a Pentax DA 645 80-160mm f/4.5 lens (four examples in the patent application) or a 90-180mm f/4.5 lens (two examples) was filed by Ricoh in Japan. The lens is stabilized (just like the 90mm macro).
This patent is probably for the lens mentioned in the latest Pentax 645 lens roadmap as a “Tele Zoom” and if released, it will probably be called HD Pentax-DA 645 90-180mm or 80-160mm f/4.5ED AW SR.
Via forumpentax.fr