Anyway, I sort of rolled my own simple version of perlbrew using a bat script to modify a symlink (Junctions) pointing to the "active" version of Perl.

If that's the case, I'm sure you'll find great value in berrybrew. Its purpose is to allow you to manage multiple versions of Perl, and even has a handy little UI that runs in the system tray to allow you to switch between them, install new versions etc.