wp_joris

When sharing the user and usermeta table between multiple wordpress 
installations using the same database, any role given to the user is only valid 
for a single wordpress installation.
This plugin ensures user roles, user capabilities and user settings are 
shared between the multiple installations. This is configured using a wp-config 
constant.
Any role set in any of the installations will be reflected in all other 
installations.
Caveats:
<ul>
<li>Compatability with wordpress multisite is unknown</li>
</ul>

Shared User Table Roles

Share user roles when sharing the user table between multiple installations.

Shared User Table Roles vs Developer Debug Tools