I am pretty sure someone would have done this before but I think it makes it a tad easier to navigate the forum.
in display.template.php I found
// Show the post itself, finally!
<hr width="100%" size="1" class="hrcolor" />', $message['body'], '
<br /><br /><a href="#">Top</a>
It just adds a nice simple anchor to the top after each post. My forum has max 15 posts per page and if they are long posts it can take a bit of scrolling to get to the buttons on the forum.
Hope someone finds it useful.