OP mentioned using biometrics as a username in combination with a password. [1] seems to imply you can add a password or pass code on xbox and I think you can do that too on a Galaxy S (?)

[1] http://support.xbox.com/en-US/xbox-360/kinect/auto-sign-in

Yes it has: https://www.youtube.com/watch?v=NpNCXxtOzAo and http://www.ibtimes.co.uk/samsung-galaxy-s3-face-unlock-flaw-...