Thanks Britt, that was extremely helpful.
However I noticed one small change was needed to ensure that the featured image that was pulled was for the actual child page and not the current page.
<?php
$child_pages = $wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_parent = ".$post->ID." AND post_type = 'page' ORDER BY menu_order", 'OBJECT'); ?>
<?php if ( $child_pages ) : foreach ( $child_pages as $pageChild ) : setup_postdata( $pageChild ); ?>
<div class="child-thumb">
<?php echo get_the_post_thumbnail($pageChild->ID, 'thumbnail'); ?>
<a href="<?php echo get_permalink($pageChild->ID); ?>" rel="bookmark" title="<?php echo $pageChild->post_title; ?>"><?php echo $pageChild->post_title; ?></a>
</div>
<?php endforeach; endif;
?>
