btsteed - 7:18 pm on Apr 8, 2011 (gmt 0)
Just an update; it's been about 5 days, and the page reappeared at position #10. The entire set of results for the phrase shifted; I didn't change anything on the page during the week. Interestingly enough, the most deserving page moved to #1 for the first that I can remember.
It's almost as if Google is giving every position on the page a few days at #1.