In the RadGridClientSideAPI example the Grid's onRowCreated client event is only firing for the first 11 rows. Thus rows 12 through 15 are not getting the class set nor events wired up. I am using version=2009.1.402.35.
I was not able to reproduce the problem. Find attached a sample website which shows that the event is thrown for all rows. Take a look at it and let me know what is different in your application.