You'll be moving stuff anyway. If you don't want to move the stuff you want to reuse into a module, how about moving the stuff you don't want to reuse into seperate modules and loading them from the script?

If you want specifics, please elaborate.

update...

here's a very simple example:

#!perl

# process input & args...

my $plugin_name = 'Some::Module';
eval "use $plugin_name;" or die "can't load module";

my $output = $plugin_name->process($formatted_input);

# format output

print $formatted_output;
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and this in Some/Module.pm:

package Some::Module;
sub process {
  my ($package,$formatted_input) = @_;
  # do stuff;
  return $output;
}
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