Well, seeing as it’s been two weeks and nobody’s even responded with so much as a “feh” I decided to muddle my way through and add it in myself. This is a total hack, and isn’t pretty by WP standards, but it works.
In /wp-admin/post.php, scroll down to case ‘edit’ and add the following after $post_title = addslashes($_POST[‘post_title’]);:
$post_author = $_POST['post_author'];
Scroll a little farther down to the UPDATE $tableposts query and add the following after post_status = ‘$post_status’,:
post_author = '$post_author',
Save and close.
Open /wp-admin/edit-form-advanced.php and scroll down to the postpassworddiv fieldset, and add this in immediately following it:
<fieldset id="postauthordiv">
<legend><?php _e('Post Author') ?></legend>
<div>
<select name="post_author">
<?php
$authq = "select * from wp_users order by ID";
$authr = mysql_query($authq) or die(mysql_error());
while ($auth = mysql_fetch_array($authr)) {
echo '<option value="' . $auth['ID'] . '">' . $auth['user_nickname'] . '</option>';
}
?>
</select>
</div>
</fieldset>
Save and close.
Done.