Awesome

Created by Kaspars Dambis konstruktors.com

Important:

• This plugin is intended for a local development environment.
• It is much easier to use Apache's virtual hosts setup and modify your hosts file locally instead of using this plugin.
• This is a MU plugin, so you should put it in /wp-content/mu-plugins/multisite-local-dev.php
• It works only with Networks where sites are in sub-folders. However, it should be easy to modify this script to support sites in subdomains.
• Blog post: http://konstruktors.com/blog/wordpress/3857-develop-wordpress-multisite-locally-using-production-database/

Network Setup (Production):

• Network home URL (blog_id 1): http://example.com/
• Singe site URLs (blog_id 2): http://example.com/extranet/
• Singe site URLs (blog_id 3): http://example.com/intranet/

Network Setup (Development):

• Network home URL (blog_id 1): http://localhost/example-dev/public/
• Singe site URLs (blog_id 2): http://localhost/example-dev/public/extranet/
• Singe site URLs (blog_id 3): http://localhost/example-dev/public/intranet/

You need to put this into your dev wp-config.php right below the Multisite related constants:

// (int) blog_id => (string) blog_path

$dev_sites = array(
	1 => '', // Network home
	2 => 'extranet',
	3 => 'intranet'
);

define('WP_CONTENT_URL', 'http://localhost/example-dev/public/wp-content');

$current_site = new stdClass;
$current_site->id = 1;
$current_site->site_id = 1;
$current_site->domain = DOMAIN_CURRENT_SITE;
$current_site->path = PATH_CURRENT_SITE;
$current_site->cookie_domain = DOMAIN_CURRENT_SITE;

foreach ( $dev_sites as $site_id => $folder )
	if ( strstr( $_SERVER['REQUEST_URI'], '/' . $folder . '/' ) )
		$current_site->blog_id = $site_id;

if ( ! $current_site->blog_id )
	$current_site->blog_id = 1;

$current_blog = $current_site;