The main purpose is to administrate different Perl Versions

Couldn't you just run a script that sets which perl is found ? On my Win32 box I have six or so versions of perl and run a batch file to set the path so that 'perl' finds the perl executable that I want. (I have a separate batch file for each build of perl.) Then %Config should contain the info I want.

If you really do need to rewrite Config.pm then it's best to do something similar to EU::FC - which leaves the existing Config files as they are, writes the new values in Config_m.pm, and loads those new values, when needed, by running perl with the '-MConfig_m' switch (or by setting the perl5opt environment variable to '-MConfig_m').

Cheers,
Rob