Show individual author rank from query of cumulative post view count for all authors

First you can replace

'posts_per_page' => '10000000000'

with

'posts_per_page' => -1

to remove the limit.

If you want to show the user rank, you can add a $rank counter in the foreach loop:

$rank=0;
// output the result: user, total postview count, latest post
foreach ($output as $user){
    $rank++;
    $profile = get_userdata($user['id']);
    $query = get_posts( array('author' => $user['id'], 'numberposts' => 1 ));

    // update the rank for each user
    update_user_meta( $user['id'], 'user_rank', $rank );

    echo '<div class="user-item">';
    echo '<p>' . $profile->user_nicename .' ('. $user['views'] .') [User Rank: '.$rank.']</p>';            
    foreach ( $query as $post ){
        echo '<a href="' . $post->post_name . '">' . $post->post_title . '</a>';
        echo get_post_meta($post->ID, get_post_views('normal'), true);
    }
    echo '</div>';
}

Update:

Calculating the rank for all the users might be a job for a cron service, for example:

1. wp-cron,
2. linux cron,
3. external cron service
4. custom cron.

Here is just one idea for part 2 and 3:

1. Create a file called mycron.php
2. Add the two code lines at the top of the file from here:
   http://codex.wordpress.org/Integrating_WordPress_with_Your_Website
3. Add your code to mycron.php
4. Increase the array_slice limit (it’s currently set to only 10)
5. Run mycron.php to test it
6. Add the mycron.php to a cron service (eg. daily)
7. Add time/memory measurements to mycron.php
8. If this gets too heavy, try to divide it to other cronjobs (maybe
   500 users per cronjob)
9. Have a large cup of coffee 😉

ps: remember to have a backup of your database.

Update 2:

Here is an exmple of your mycron.php file, if you want to try it out in your WordPress root folder:

<?php 

define('WP_USE_THEMES', false);
require('./wp-blog-header.php');

global $wpdb;
$topuser = array();
$html = "";

// query all posts by each user
$users = $wpdb->get_results("SELECT ID FROM $wpdb->users ORDER BY ID"); 
foreach ( $users as $user ) {       
    $query = get_posts( array('author' => $user->ID,  'posts_per_page' => -1));
    $counter = 0;

    // get each post of a user
    foreach ( $query as $post ){
        $views = absint( get_post_views('normal') );
        $counter += $views;
    }
    $topuser[] = array( 'id' => $user->ID, 'views' => $counter);
}

// function to sort array based on views count
function sortViews($a, $b) {
    return $b['views'] - $a['views'];
}
usort($topuser, 'sortViews'); // sort the array

// output the result: user, total postview count, latest post
foreach ($topuser as $user){
    $rank++;
    $profile = get_userdata($user['id']);
    $query = get_posts( array('author' => $user['id'], 'numberposts' => 1 ));

    // update the rank for each user
    update_user_meta( $user['id'], 'user_rank', $rank );

    $html .= '<div class="user-item">';
    $html .= '<p>' . $profile->user_nicename .' ('. $user['views'] .') [User Rank: '.$rank.']</p>';            
    foreach ( $query as $post ){
        $html .=  '<a href="' . $post->post_name . '">' . $post->post_title . '</a>';
        $html .=  get_post_meta($post->ID, get_post_views('normal'), true);
    }
    $html .= '</div>';
} 

echo $html;

printf(" Perfomance: %s queries in %s seconds ", get_num_queries(), timer_stop(0));

echo (file_put_contents("/path/to/ranks.html", $html)>0)? "Success!":"Problem writing to file!";