This will allow the post editor to be moved like the other sortable post boxes.
function move_posteditor( $hook ) {
if ( $hook == 'post.php' OR $hook == 'post-new.php' ) {
wp_enqueue_script( 'jquery' );
add_action('admin_print_footer_scripts', 'move_posteditor_scripts');
}
}
add_action( 'admin_enqueue_scripts', 'move_posteditor', 10, 1 );
function move_posteditor_scripts() {
?>
<script type="text/javascript">
jQuery('#postdiv, #postdivrich').prependTo('#your_meta_box_id .inside' );
</script>
<?php }