GDM login without using a password

[Roey Dror]

I've searched around the internet for a way to allow a user to login
into GDM without using a password.
I know that GDM has an automatic login feature, but that's not what I'm looking.
I really do not wish to create a user with an empty password, in order
not to compromise the entire system security.
I found a mini-HOWTO which suggests using the pam_filelist module.
Unfortunately, I couldn't find this module in the ports system.

Is there any other way to allow this user to login without using a
password only using GDM?

-- 
Roey