There are quite a few good Pentax blogs, but like the good guys here, Pentax seldom attracts loudhailers and exhibitionists types (ie. like Ken Rockwell).
His stuff is usually full of opinions that shifts here and there and very often unproven, sometimes laughable .
Anyway, IMO, its not that important whether there is or not a Pentax version of Ken Rockwell, we pick up photo know how on any good photograph site, whatever brand the owner of that site is using.
I'd like to see myself as being able to see past the brand speak and gear pushing and see the basis of the technique being used.
An example of this is Strobist.
David Hobby does not promote any brand. Whatever it takes to get the effect is the bottom line.