I'd say sharing modules is setting yourself up for a world of hurt eventually.

Those perl versions must be separate for a reason (or why would anyone bother making them separate?). They need to have matching separate perl modules.

Can you get away with using CPAN exclusively for the developer perl, and only packaging up the stable production perl modules as RPM's? If you go through the trouble of packaging up, would your bosses let you contribute those packages back to your distribution maintainer for others to use?