byte, my understanding is that hot pixels are simply noise manifestation of digital imaging sensor (also named 'dark noise', or 'image noise'). More of them appear when the sensor overheats, thus prolonged use of live view is one scenario which could trigger more of them to appear, very long exposures (night shots) is another. See for example this from Hasselblad:
"Image noise in the Hasselblad H3D-II has been significantly reduced by improving the cooling of the sensor, achieved by attaching to the CCD a physical heatsink, which dissipates the heat generated to the entire camera body and considerably lowers the temperature of the system"
I found it strange that a reputable site can test the same camera, and does not even mention the issue which was already widely known and discussed elsewhere, also acknowledged by Pentax. Not seeing something which many other people saw is significant, and should lead to: "why I am not seeing this?" or "how is my test different?" or "are there different K20D bodies being sold?" etc, etc.
BTW, I do not believe that Pentax fix addressed the issue, but as at this stage I can not re-test myself, I am not in a position to contribute anything more.
darius, I believe hot pixels rarely show up during normal usage. However they may appear after extensive use of live view as said by reviewers of other website.