*Ian zooms in to save the day*

Actually, based on the way smarty works, and the fact that the header is always built before the footer, copying the following code from header.tpl to footer.tpl results in a second breadcrumb thing

Code
{if $config.ENABLE_MAIN_PORTAL}
<a href="{$config.BASE_URL}/ubbthreads.php">{$config.COMMUNITY_TITLE}</a>
{else}
<a href="{$config.HOMEPAGE_URL}">{$config.HOMEPAGE_TITLE}</a>
{/if}
{if $breadcrumb}
 &raquo; {$breadcrumb}
{/if}

A spruced up example can be seen here.