Custom GDM greeter for Tails: 
http://tails.boum.org/todo/TailsGreeter/

Code QA:
pylint --rcfile=.pylint.d/.pylintrc tails-greeter.py
pylint --rcfile=.pylint.d/.pylintrc tailsgreeter

Disabled reports:
C0103 (Invalid name) - python's name convention is not universal and conflicts with d-bus
C0301 (Line too long) - matter of taste
E1101 (...has no member) - triggered by d-bus methods
R0201 (Method could be a function) - matter of taste
R0903 (Too few public methods) - matter of taste
R0902 (Too many instance attributes) - matter of taste
R0904 (Too many public methods) - matter of taste

QA target: 9.5

Test helper:

#!/bin/sh

rm tails-greeter.deb
aptitude -y purge tails-greeter
wget http://dev.machine/tails-greeter.deb
dpkg -i tails-greeter.deb
service gdm3 restart