This is stopping me from upgrading to the latest version of Kubuntu, and I realise that there are solutions out there but I would rather not have to resort to a third-party solution.
If you mean the oxygen-gtk3
A wish (needs-packaging): https://bugs.launchpad.net/ubuntu/+bug/825858
It has a link to the "HOWTO: gtk3-engines-oxygen for gtk3 apps": http://kubuntuforums.net/forums/index.php?topic=3118994.0
Peeking to the kubuntu-devel irc: http://irclogs.ubuntu.com/2011/12/21/%23kubuntu-devel.html
_Groo_ Riddell: btw it would be nice to add gtk3-engines-oxygen to the builds 17:55 _Groo_ Riddell: my desktop is much more pretty that way :D 17:55 Riddell yes I think that's on the precise todo 17:55
Maybe with the Kubuntu 12.04...