Do you know of a way to move the elements around on the login screen? Specifically I’d like to move the bottom panel to the top.

I’ve actually reported this as a bug on Launchpad (https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/524497#) and even tried fiddling with the greeter’s source code myself, but it was just useless guesswork with my non-existent GTK knowledge.