Pentax does not currently sell any TCs. However, the lens road map they published last year listed a 1.4 TC. It might be worth waiting to see if Pentax releases it.
I have been looking forward to it to pair with a 300 f/4 lens. But I don't have any information about which lens the new TC will support.
|AF4_2483 Surfing the Serengeti by DaveInHouston|
from Hot Air Balloon view
|Peregrine Falcon by Psychic1|
from Best Wildlife Photo of the Week - 4