Yes there is a per forum search in 6.4 in the postlist extra information box NOT FOOTER.
You can add this code where up higher in postlist.tmpl near the top
Find this:
$changetext
$changestop
</td>
</tr>
</table>
</td>
</tr>
</table>
</td>
</tr>
Place this under it:
<tr>
<td align="center" class="lighttable">
<form method="post" action="{$config['phpurl']}/dosearch.php">
<input type="hidden" name="Cat" value="$Cat" />
<input type="hidden" name="Forum" value="f$bonumber" />
<input type="hidden" name="daterange" value="0" />
<input type="hidden" name="where" value="bodysub" />
{$ubbt_lang['SEARCH_FORUM']}
<input type="text" name="Words" class="formboxes" />
<input type="submit" name="textsearch" value="{$ubbt_lang['TEXT_SEARCH']}" class="buttons" />
</form>
</td>
</tr>
You can see it in action right here
http://www.reeftalk.com/ubbthreads/postlist.php/Cat/0/Board/UBB1