There is progress of the case, although nothing is official so far:-
http://ricehigh.blogspot.com/2009/09/k-7-vertical-line-issue-silently-solved.html
It seems that Pentax/Hoya has been trying hard to eliminate/hide the problem by firmware, the problem and phenomenon is reduced, but it is still not totally eliminated.
Let's wait and see what other affected K-7 users will report in due course.