More info here:Packages for the release of the KDE Software Compilation 4.6.5 are available for Kubuntu 11.04 bringing you new versions of the KDE Platform, Plasma Workspaces and KDE Applications .
It's great that the Kubuntu team provide these monthly releases which are basically bug fix releases. It is also great that the KDE team take special care not to break stuff so people don't have to backport their patches. Just get the upstream release, compile and package it and you're golden.
I might just become a long time Kubuntu user after all