How to seriously edit Windows 7 logon screen?

Hello,

Straight to the point, I want to edit my login screen so that there is no username, no user image, no password box etc. but an image. As far as I researched, I know that username, user image etc can be hidden, but I'm curious about the password box. What I want is to enter my password like how you enter cheats in older GTA games, and what I've read in internet so far made me think that if I change password box's coordinates to somewhere out of the screen, since the password box automatically gets focused, I should be able to blindly enter my password.

So, how? Thank you guys for your help in advance.