The final results of Mike's calibration of the Optoma HD37 resulted in a very good overall picture. His efforts, however still left a tinge of yellow (or perhaps yellow green) in skin tones, and a very slight shift (toward yellow) in a typical blue sky.
I would expect that further tweaking and adjusting, could eliminate most or all of that shift. My own brief attempts, however, to correct via minor adjustments to the grayscale balance did not yield results.
I believe the minor fix will lie somewhere in the color management system. But then, I have only dabbled in calibrating projectors over the years.
Those of you with your own gear should be able to get that last 5-10% right, by investing a little extra time.
For those of you just plugging in our settings, you should still have generally very good color accuracy, and a well balanced picture, but for that minor shift.