I can't answer your question. I can offer this, if you are using local::lib + App::cpanminus, perhaps go "all the way" and utilize perlbrew to create an installation along side of your current system perl + local set up to see if that suited your needs first? If so, then you don't even haave to touch your localized environment that has been built on top of system perl. Is it safe to assume you're really using system perl + a significant investment in modules installed as a non-privleged user? Are the XS modules darkpan (not on CPAN) or are they just the result of some heavy "tweaking"? It sounds like you want to recompile the XS modules "in place", maybe? The nice thing about perlbrew is that it allows you to achieve total isolation. cpanm also works with whatever perl is in PATH (or it can be fetched via perlbrew). Just some ideas there - don't know much detail about your set up or constraints.