Was taking a look at various distros and it looks like OpenSUSE Tubleweed (which is a rolling release) is available for both PPC64 and PPC64le.
Tested on x64 and x1000.
On PA Semi 4GB RadeonHD 6870 it was usable but unstable.
I believe recent updates are LE only, no Altivec (IBM POWER made for), just like with Debian and many other distros.
Once laptop goes live I advise sending boards to Linux teams so maybe PPC64BE+Altivec will be supported again.
On 2xi3 2Ghz 4GB IntelHD 4000 it is stable and usable, it shows PPC distros
need just a bit more stable kernels and tested builds.
+ Constant Update (Rolling Release)
+ Comes with MATE
+ Built on OpenSUSE
- Not the fastest distro
Leap also exists for PPC, but was unable to make it work with kinky x1000 kernel
trickery.
https://www.opensuse.org/#Leaphttps://en.opensuse.org/Portal:LeapLeap is also openSUSE based, but stable and very complete.
It is "new OpenSUSE", but PPC64LE only
http://software.opensuse.org/distributions/leap/ports