Much like Leon's additional metabox holder above the default TinyMCE editor, this will place a full width container above the text field by hacking apart the form tag via post_edit_form_tag action

gistfile1.php

<?php

add_action('post_edit_form_tag', 'ebs_seo_cp_modify_form_tag');
function ebs_seo_cp_modify_form_tag() {   
    $screen = get_current_screen();
    if ( $screen->id != 'location') { return; } //change to custom post type
    global $post;
  
    //lets close the <form> tag
    echo '>'; 
  
    //insert a new sortable postbox
    echo '<div id="post-head" class="metabox-holder columns-1"><div id="postbox-container-3" class="postbox-container">';	
  
    //process "head" metaboxes
    do_meta_boxes( get_current_screen(), 'head', $post );
  
    //button everything up.
    echo '</div>';
  
    //we leave the trailing > off, as it is supplied by the <form> tag we are hooked into
    echo '</div';
}

?>

<script type="text/css">
/* we need to declare some CSS so wordpress recognizes our new meta box container */
#postbox-container-3 {
    float:none;
}
 
#post-head #head-sortables {
    min-height:50px;
}
</script>