I have been wanting to be able change the logon image for a while, and the authui.dll replacement does work for me. For that I want to thank all of you guys. The problem I had with that copy of the authui.dll file is that it leaves a opaque outline to your user image. I did a little search online and found this forum posting:
Here they were trying to mod their logons for vista, and I just replaced that copy of authui.dll file and it gave me a near exact copy of the vista logon. It still allows you to run LogonVista as well. It Has been working on me, hopefully it wont crap out on me in the future.