Thiago Macieira of Intel's Open-Source Technology center mentioned the user-session-units work this weekend on the KDE core development list. Thiago has been working on this with Auke Kok, another Intel engineer. "One of my colleagues at Intel has begun working on a project to have systemd launch and manage the user session."
These files are currently housed on GitHub and the README describes the goal of this work as to "provide an easy way for people to collect, share and deploy systemd user session installations and help test the systemd user session core code."
Besides KDE, Auke Kok has worked on systemd user session unit files for Xfce4, XBMC, and Enlightenment desktops.
Thanks to Mark for mentioning this news.