Originally Posted by PaulAndAPentax 
Oh what I wouldn't do for a 400 f/2.8 (AF) or a 500 f/4
so you're saying that birders will be happy too...I love shooting birds....
Hi Paul,
I know the designs are done or being completed for certain focal lengths (those above 300mm...). Don't hold your breath for an AF 400/2.8 though! The side bonus is that I suspect with time, those third party manufacturers will take notice of Pentax's success and start producing more options in the Pentax mount.
Besides, I think your listed focal lengths are too short...
Cheers!
Marc