The “Child Pages Shortcode” plugin, block template

by

Try this:

// Wrap <li> tags around each template item.
add_filter( 'child-pages-shortcode-template', 'wpse_113253_child_pages_shortcode_template' );

// Wrap <div> and <ul> tags around everything.
add_filter( 'child-pages-shortcode-output', 'wpse_113253_child_pages_shortcode_output' );

/**
 * Wrap <li> tags around each template item.
 */
function wpse_113253_child_pages_shortcode_template( $template ) {
    return "<li>$template</li>\n";
}

/**
 * Wrap a <div> and <ul> tags around everything.
 */
function wpse_113253_child_pages_shortcode_output( $html ) {
    return "
<div class="row-fluid">
    <ul class="thumbnails">
        $html
    </ul><!-- end .thumbnails -->
</div><!-- end .row-fluid -->
";
}

Note: I didn’t install the plugin to test this code.