I got that part down. I was thinking something like this.
<?php
$blah = "something here";
class qa_html_theme extends qa_html_theme_base
{
function nav_list($navigation, $navtype)
{
if ($navtype=='main')
$navigation['custom']=array( 'url' => 'http://your-page/', 'label' => '$blah');
qa_html_theme_base::nav_list($navigation, $navtype);
}
}
?>
If that makes sense.