Hello,
You can always add a repository for what you need. I'm not an Ubuntu user myself but a quick Google search turned up this:
https://help.ubuntu.com/community/Repositories/Kubuntu. You can add the Backports repo to get newer software or even Beta Backports.
Keep in mind though that if you use a version that hasn't been thoroughly tested of any software outside from what you have in stable repos, you might encounter yourself with broken stuff that you'll need to take care of searching forums, fixing stuff, ...
You cannot have the best of both worlds, the latest stuff and stability. That's why there's such a lag between stable and 'testing', everything needs to be tested over and over again before considered stable.
Kind regards,
Eric