Arch Linux provides packages in the KDE-unstable repository
# pacman -S plasma-next
Three options to try it out:
1) For 14.04, on Kubuntu, Project Neon is available as PPAs which offers frequently updated development snapshots of KDE Frameworks. Packages will be installed to /opt/project-neon5 and will co-install with your normal environment.
sudo apt-add-repository ppa:neon/kf5 apt update apt install project-neon5-session project-neon5-utils project-neon5-konsole
2) For Utopic (will be 14.10) releases of KDE Frameworks 5 and Plasma 5 are being packaged in the next PPA. These will replace your Plasma 4 install.
sudo apt-add-repository ppa:kubuntu-ppa/next apt update apt install kubuntu-plasma5-desktop apt full-upgrade
3) Finally the Neon 5 Live image, updated every Friday with latest source from Git to run a full system from a USB disk.
Packages are provided in KDE:Frameworks5 and KDE:Qt5 repositories, for openSUSE 13.1:
zypper ar http://download.opensuse.org/repositories/KDE:/Qt5/openSUSE_13.1/ Qt5 zypper ar http://download.opensuse.org/repositories/KDE:/Frameworks5/openSUSE_13.1/ KF5
and openSUSE Factory:
zypper ar http://download.opensuse.org/repositories/KDE:/Frameworks5/openSUSE_Factory/ KF5
For more details see this page.