I can't speak for Seth, but I'm fairly sure the answer here
is "use bind
mounts". Seth is very big on the FHS, and in the FHS, that's where the
buildroots and other stuff for mock are supposed to live. I've asked
about this long ago, when starting to use mock for the build system, and
that was the answer. Seriously, bind mounts are neither complicated,
nor problematic, though I haven't done a ton of testing with NFS.
The fhs is our friend. :) However I don't think we're suggesting
changing the default location for mock just making it possible for
someone else to do something like that. And if we can do that securely
then, sure.
-sv