I think Pentax have no interest on full-frame.
On their head is present only the medium format and nothing other things.
About the article, official canon source said that a full-frame sensor cost 500 dollars while an aps-c sensor cost only 50 dollars so, unfortunatelly, the difference isn't limited at only 100 dollars between the two solutions.
However i don't think this is a real problem as soon are developed good aps-c solutions.
For example with the pentax k-x you could obtain nice shoot even at 6400 iso, if you improve it using better electronics and algoritms isn't distant the day when an aps-c camera could obtain the same quality possible now using a full-frame.
And even now, despite remain some difference, the result aren't bad at all.