Thanks for the suggestion about 02packages.details.txt. I forgot to mention that I'm in a behind the firewall situation where I can't use CPAN so I've written an install script to run through the Makefile.PL, and dmake steps for me. But after a few years and a mix of old and new servers I need to check which modules are already installed. In the near future I plan to add my own local CPAN mirror.