As an example, see: http://git.yoctoproject.org/cgit/cgit.cgi/meta-mentor/tree/conf/distro/include/sstate.inc
Final implementation may be related to bug 5265
Updated url: http://git.yoctoproject.org/cgit/cgit.cgi/meta-mentor/tree/meta-mel/conf/distro/include/sstate.inc Also, uninative may significantly obsolete all of this anyway.
The widespread use of uninative means we no longer need to do this, resolve as obsolete.