Don't you just hate searching for members?

[The Man]

Haha it turns out you don't need to hack anything for this. Just go into the template and add this:

<!-- quick search and memberlist title -->

<form action="memberlist.php" method="post">
<input type="hidden" name="s" value="$session[sessionhash]">
<input type="hidden" name="action" value="getall">

<table cellpadding="0" cellspacing="0" border="0" bgcolor="#000000" width="100%" align="center"><tr><td>
<table cellpadding="4" cellspacing="1" border="0" width="100%">
<tr>
<td bgcolor="#012033" colspan="6">

<table cellspacing="0" cellpadding="0" width="100%"><tr id="cat">
<td><largefont>$[/i]bbtitle Members List</largefont></td><td align="right">

<smallfont><b>Quick Username Search:</b>
<input type="text" class="bginput" size="35" name="ausername" value="" style="font-size: 11px;">
<input type="submit" class="bginput" name="submit" value="Go!" accesskey="s" style="font-size: 11px;"></font></td>

</form>

</tr></table></td>

<!--/quick search and memberlist title-->

in place of the memberlist title table data cell.

That'll give you something along the lines of:

$bbtitle Members List Quick Username Search:

Good times.