How to load aggregated styles / js in an 'external' script via DRUPAL_BOOTSTRAP_FULL?
Here's the gist of it (w/ commentary).

&lt;?php
// ... your code 
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

// get current theme and it's variables
$current_theme = variable_get('theme_default','none');
$themes = list_themes();
$theme_object = $themes[$current_theme];

// uncomment to display structured information about $theme_object
// var_dump($theme_object);

// get current theme path
$theme_path = dirname($theme_object-&gt;filename);

    // get path of each stylesheet from current theme
  $final_stylesheets = array();
    if (!empty($theme_object-&gt;stylesheets)) {
    foreach ($theme_object-&gt;stylesheets as $media =&gt; $stylesheets) {
      foreach ($stylesheets as $name =&gt; $stylesheet) {
        $final_stylesheets[$media][$name] = $stylesheet;
      }
    }
  }
  foreach ($final_stylesheets as $media =&gt; $stylesheets) {
    foreach ($stylesheets as $stylesheet) {
            // will print relative path to the stylesheet
            // here you can wrap each stylesheet in &lt;link type="text/css" ....&gt; tags
            // and compose the output for hte head section of your script
            print $stylesheet;
    }
  }

    // Do same for scripts
  if (!empty($theme_object-&gt;scripts)) {
    foreach ($theme_object-&gt;scripts as $name =&gt; $script) {
      $final_scripts[$name] = $script;
    }
  }
  foreach ($final_scripts as $script) {
    print $script;
  }
?&gt;


all you have left to do is to wrap each $stylesheet and $script in appropriate tags and insert that into the head.