misapplied thermal grease have been floating around for a year now, and it doesn't look like the recent bump to Santa Rosa has changed anything. A reader at the MacRumors forums noticed his week-old MBP getting a little hot, so he bravely decided to pull the unit apart to check things out and found what he estimated to be forty times too much paste applied to the logic board. There are also a few threads on the Apple support site with similar pics of MBP logic boards slathered in grease, so this doesn't appear to be an isolated issue. Apple hasn't commented yet, but seeing as it managed to cool things down last time with a firmware update, we wouldn't expect too much fanfare when this finally gets resolved.
Read - MacRumors thread
Read - Apple Discussions thread