Hey mate,

(I know this is quite old now but I thought it might help if someone else is looking for the same thing...)

I was checking out the KB last night and same thing caught my eye as well... When I searched, I came across this which didn't have a reply... so I decided to take things to my own hands... This may not eb cleanest solution but it worked for me and it will definitely break with a new update... so you might want to keep track of your changes...

I added below code to index.php in kb folder
below this line --> "require(CLIENTINC_DIR.'header.inc.php');"
?>
<?php
if ($cfg && $cfg->isKnowledgebaseEnabled()) { ?>
<div class="search-form">
<form method="get" action="faq.php">
<input type="hidden" name="a" value="search"/>
<input type="text" name="q" class="search" style="width: 680px;" placeholder="<?php echo __('Search our knowledge base'); ?>"/>
<button type="submit" class="green button"><?php echo __('Search'); ?></button>
</form>
</div>
<br>
<?php } ?>
<?php
above this line --> "require(CLIENTINC_DIR.$inc);"
This works for the latest version of OS ticket at the time I am writing this.. I think 1.15.3.1...

It bring the search box from the landing page over to your KB page...