You can also now use get_called_class() which saves you even needing the static member variable.
http://php.net/manual/en/function.get-called-class.php
Example:
class Boo {
public static function reaction() { return get_called_class(); }
}
class Yay extends Boo {}
var_dump( Boo::reaction() );
var_dump( Yay::reaction() );
Like you, I’ve been waiting a looooooong time for late static binding :)