Please, is there any module for external authentication support?

For example I have a server with private web zone for users, which is authenticated by apache mod_auth. PHP can read login name of logged-in user from enviroment ($_SERVER['REMOTE_USER']). I want to prevent double auth, so i want eTicket to guess login from REMOTE_USER.

To make it nice configurable, 3 config options should exist:
1) Whether to use external auth or not
2) Whether to autocreate user, if REMOTE_USER is set, but is not found in our SQL database
3) Default options (group, etc...) for autocreated user

Would it be possible to implement such feature please? I'm ready to cooperate in that case.

You can do this but you would need to modify the function login() located in class.ticket.php