Sorry for the delay in updating this situation...
After picking up my replacement K7 (making sure the serial # was nowhere near my two originals), I immediately tested the issue (before updating firmware) and alas, I have the same problem... But what is odd, is that the firmware is listing as 1.00.00.04, which I don't recall ever hearing about before... can anyone confirm that this the version that was shipping with the K7 originally?
I'm not sure what to do... I figure I might as well try installing .13 again to see if maybe this whole situation is an anomaly and it might magically be fixed by doing things in a different sequence.
For the record, I've been testing this whole time by shooting a 2 to 4sec exposure @ ISO 800 - 1600 / f8 with the lens cap on... I also tried covering the lens with the palm of my hand, thinking some light might be leaking in from the lens cap causing weird effects - Nope. Has anyone else tried doing a longer exposure to see what results they get?
I hate to say it, but I'm starting to smell a D700 in the not too distant future... Just kidding... Not really... I don't know... What's a proud Pentaxian to do?