More info..
after reading many of the posts on here about multiple blogs and single users it seems its a common problem but one that has only been solved if you’ve got everything running on the same database.
As I only need shared registration I’m looking at a hack of the wp_insert_user() function in registration.php to cross write the data to the other domains database. This would need a tweak of the permissions in the cpanel of each domain to allow access from a new domain (other than localhost).
This should maintain two sets of user data simultaneously.. I think.
Possible?
