Addendum:

> true little-endian is supported at least by MPC8xx/e200, e300, e500, PPC4xx
> and PA6T/PWRficient.

Apparently, POWER6/6+, POWER7/7+ and POWER8 can be added to this list.

http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-June/082797.html
http://lists.gnu.org/archive/html/qemu-ppc/2013-08/msg00047.html
http://lists.debian.org/debian-powerpc/2013/09/msg00050.html