If you go to the New York State Public High School Athletic Association web site and go to the classification page classification, there is a link to a table of the 2009-10 classification numbers.
If you use the drop-down menus you can see the enrollment numbers for next year for Section VI (or any other section, for that matter).
I'll issue a disclaimer right now: that's some raw data, and the site has a note saying the numbers have to be approved in January (but it seems like those numbers are what they are) and this may be conjecture on my part.
But check out the numbers.
Notable switches -- as long as the same cut-off numbers are used -- include Grover Cleveland splitting into two programs (actually they already are: but athletically Grover Cleveland is lined up as Class C (!) and International Preparatory School at Grover is lined up as a D).
Another quick scan of the numbers showed Sweet Home becoming an AA by just two students (951 puts it in the 950-and-over Class AA).
The breakdown of the enrollment numbers for 2008-09 is on the Section VI Web site.
Happy clicking and calculating.