As you already know, Plasma mediacenter 1.3 beta is released on 3rd June.
Many distros like Fedora, openSUSE, KUbuntu have already packaged this beta in their repositories
So to make life of Archers easier, I have uploaded PKGBUILD for Plasma mediacenter 1.3 beta on AUR.
to install use your AUR helper,
If you get any bugs please report on bugs.kde.org
PS: This is first package I am going to maintain on Arch Linux User Repos..