it was suggested to me that I should post my patch to this ml. So here
it is.

Located at

http://dev.gentoo.org/~ali_bush/portage_parent_repo_support.patch

you will find a patch for repoman to support a hierarchy of overlays by
allowing an overlay to specify its parents. I have recently been using
this patch over java-experimental to solve the absolute mess "we" have
created there.

I would like to thank zmedico for the help he has given me on this.

Thinks to note/discuss.

An overlays parents are specified as a space separated list of
pkg_names, with a key of masters, located with a file metadata/layout.conf.

eg

masters = gentoo java-overlay

gentoo is implied and assumed so is not necessary ( and is actually
filtered out within the code as it isn't an overlay). The reason I have
this is to maintain compatibility with other package managers and
because being explicit is a good thing. If we were to change this then
it would be sensible to also change the file name. Other package
managers also store other variables within this file. I propose that
they are just ignored. I have not currently implemented the validation
classes that can be used by KeyValuePairFileLoader.