My first try uploading anything here! I wanted a gdm theme to match my wallpaper and icon theme, so I threw together this.
The software I used to get the screenshot rendered it on a standard screen, which as you can see messed it up a little bit. On a widescreen display everything is pretty much centered and it doesn't look so squished.
I got the background from gnome-look but for the life of me I cannot find it again. The icons are from the Lila Icon set: http://lila-theme.berlios.de/.
IMPORTANT: You need the font Gentium. It can be downloaded here: http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&item_id=Gentium_download . They have a .deb version as well if you do not know how to install a .ttf.
HOW TO INSTALL: Simply download the file. Then open up the login screen manager System>Login Window. Click the local tab and drag the .tar.gz file into the table. Voilà, new gdm theme.
Hope someone can get some enjoyment out of this.