Paul, excellent mod, really like it. I use it for Top 100 posters, so I needed to add poster's position number (you can get lost in this many posters).
If someone wants to do this, edit this template:
Top_Posters_Bit
find:
HTML Code:
{vb:raw posts.username}
add
before:
HTML Code:
{vb:raw posts.row}.
As posts.raw isn't defined, you need to create it. Edit plugin Top posters that uses hook misc_start (all plugins have same name, so look for hook).
Find:
PHP Code:
$posts['userid'] = $posts[$col]['userid'];
$posts['username'] = $posts[$col]['username'];
$posts['postcount'] = vb_number_format($posts[$col]['postcount']);
$templater = vB_Template::create('Top_Posters_Bit');
$templater->register('posts',$posts);
$toppostrow .= $templater->render();
Add right before or after this code:
PHP Code:
$posts['row'] = $row+1;
That's it, you have users postion before users name.

I attached modified file.