We've been regularly building kdelibs from trunk for about a week now and are expanding coverage to other core KDE SC modules. It won't be long until we're building all of KDE trunk (what will eventually be KDE 4.7).

http://my.cdash.org/viewSite.php?siteid=2793

I've made some local improvements to the KDE nightly build scripts that I'll start contributing back upstream as well.