Think about using par for your setup. It allows you to build an all inclusive par or executable for your project. You can then have a true frozen gold copy for qa -> release and know that all of your modules and dependancies are locked in time for a release. If you can't use that or some other better way, patching the perl binary as long as the same string length is used should work, as should doing the same through the lib tree. but that seems awfully messy to me.