Multiple WordPress Installs Sharing Users from Main WP Install?

I recently downloaded the WPMU Dev user synchronization plugin to pull user tables from my main site to my sub sites.

Unfortunately the ‘auto update’ plugin now required by WPMUDev plasters your admin panel with advertisements for their products unless you are willing to pay hundreds of dollars to them every year.

I am not a fan of these blackmailing tactics (Having to pay to remove inconveniences that they installed) so will not be using their plugin.

Don’t get me wrong, I don’t mind paying for a good plugin, $40 is very reasonable infact. But I do not like underhand tactics such as this.

Is there another plugin out there for user synchronization across multiple wordpress installs, or will I need to hire plugin developer to custom code one (Something I am very willing to do).

I found an article on this

(http://codex.wordpress.org/Installing_Multiple_Blogs#Multiple_Databases.2C_Same_Users)
(http://xentek.net/articles/528/implementing-the-wordpress-shared-users-table-trick/)

but I am not sure how this propogates to multiple databases, and all my DB’s are currently set up with the same wp_ tabel structure.

Any help would be greatly appreciated!

Kind Regards

Oli