System connection implementation is progressing in Plasma NM. Andrey Borzenkov took over the task of maintaining Gökçen Eraslan's system connection implementation. It is working, I am using it right now but it still needs some adjustments before we push it to master branch though. Anybody willing to test it can get the patch in http://git.reviewboard.kde.org/r/100947. Please report bugs in the system connection bug entry in http://bugs.kde.org/204340.
Meanwhile, I created a nm09 branch to let others, specially Jiří Klimeš and Andrey Borzenkov, implement the necessary changes for NetworkManager-0.9 support. The code in that branch does not work with NetworkManager-0.8, only with NetworkManager-0.9.