The closest option is the Tamron/Pentax DA18-250mm and the Sigma 18-250mm OS HSM. The former is no longer manufatured but it can be easily purchased 2nd hand from the PF marketplace, and reliable 2nd hand sellers like Keh.com and Adorama. The latter (Sigma) is more expensive, can be purchased new, but the lens OS is not compatible with the camera IS (and must be swiched off).
I have the DA18-250mm and I compared it with my older Panasonci FZ20 equipped with a 12x zoom. The DA18-250mm + K-7 gives me better IQ by far IMHO, and the images can be cropped 100% and still give a better IQ than the FZ20 at 12x.
Hope that the comment may help,