If it's not, it downloads the specific version of that module from CPAN (assuming it's available) and builds and installs it, including all depedencies

I would recursively install the version of the dependancy that you require by hand ^update, or you can still end up with inconsistent installations.

I have a configuration file that lists the dependancies at the top, items that depend on them at the bottom, and a repository of the tar.gz files called out in that configuration file that I use for builds. I can do a full recompile and install of everything I need for my system starting from a bare known OS install with a single command.

Building the configuration file the first time, now that is the pain.