I just installed Lubuntu from the July 26/11 daily iso, after the install process had finished, my user name was in the list of users. After updates, only the guest user and other were available. Choosing other, allows me to enter my user name and password, allowing to access the desktop.
DistroRelease: Ubuntu 11.10
Package: lightdm 0.9.2-0ubuntu4
ProcVersionSignature: Ubuntu 3.0.0-7.8-generic 3.0.0
Uname: Linux 3.0.0-7-generic i686
Date: Thu Jul 28 19:09:26 2011
InstallationMedia: Lubuntu 11.10 "Oneiric Ocelot" - Alpha i386 (20110725)
UpgradeStatus: No upgrade log present (probably fresh install)