<?
add_filter( 'user_trailingslashit', 'no_page_slash', 70, 2 );
function no_page_slash( $string, $type ){
   global $wp_rewrite;

	if( $type == 'page' && $wp_rewrite->using_permalinks() && $wp_rewrite->use_trailing_slashes )
		$string = untrailingslashit( $string );

   return $string;
}
?>