After reading through all the wonderful response, I can't add too much... other than my perfunctory hat-tip to "A Nation Deceived."

If you haven't already done so, take some time to read through the report, "A Nation Deceived"
http://www.nationdeceived.org/

There's an executive summary to get your feet wet (http://www.accelerationinstitute.org/Nation_Deceived/Executive_Summary.aspx), and then you can plow into the full report for all the gory details.

The executive summary is probably a better introduction for whatever administrator you're trying to persuade. They can always find their way to the complete report should they be so inclined.

This article might also be of use, because it addresses some of the concerns of NOT putting your child into an appropriately challenging environment:
What a Child Doesn't Learn
http://www.wku.edu/academy/?p=430

Our son skipped K, and started 1st @ age 4y11m. He just completed a second skip from 4th into 5th and is doing very well, both academically and socially. I can't begin to imagine what a pickle we'd be in had we started him out in K... or worse, followed the popular approach 'round these parts and red-shirted him.

Lastly, for a giggle or two (which will probably come in handy about now), be sure to check out Hoagie's "Ridiculous Things I Heard Today" (http://www.hoagiesgifted.org/ridiculous_things.htm)
You can compare the nutty & frustrating things you are hearing to what others have heard in their encounters with teachers, principals and others.

Being offended is a natural consequence of leaving the house. - Fran Lebowitz