Hey Pete. This doesn't really involve exporting or manipulating the XML from Director but I used the Director PHP API and modified the Supersized! script on my homepage so I could manage the image slideshow via Director and not have to worry about it manually. Basically I set it up to as a "smart album" so any images I tag with "Homepage" in Director are pulled into the homepage image rotation. There may/likely be a more elegant solution, but this works and was fairly painless to get functioning the way I wanted. I've been toying with the idea of expanding it to make the actual portfolio pages behave in the same fashion, but just haven't had the time.

My site can be viewed at http://photography.thewmatt.com/ and you can simply view source to see the generated code. Good luck!

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Here's the code I used:
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<script type="text/javascript">
jQuery(function($){
    $.supersized({
   
        //Supersized! Variables Here, removed for clarity
        //Functionality
        slides    :  [
                    <?php
                       include('DirectorPHP.php');
                       $director = new Director('Director Install API Key Here', 'URL/Path to Director Installation Here');
                   
                        $bground = array(
                            'name' => 'bground',
                            'width' => '1280',
                            'height' => '1280',
                            'crop' => 0,
                            'quality' => 80,
                            'sharpening' => 0
                        );
                       
                        $director->format->add($bground);
                       
                        $tags = array('homepage', 'all');
                        $content = $director->content->all(array('tags' => $tags));
                       
                        foreach($content as $images) {
                            echo '{ image : "' . $images->bground->url . '"},';
                        }
                    ?>
                    ]
    });
});
</script>