Warning!! What follows is just my curiosity in trying to solve the problem. It works as far as I have tested it, and that is exactly as far as you can see from the simple code that follows. Critisisms invited.

Using this main program

#! perl -sw
use vars qw/@scanners/;
use strict;
use constant PLUGINS => 'c:/test/plugins/*';

BEGIN {
    @scanners = glob PLUGINS;
    for(@scanners) {
        require $_;
        warn $@ if $@;
        my ($module) = m!.*/([^\.]+)\Q.pm\E$!;
        $_ = eval{ "$module"->new() };
        warn "Attempt to load: $module failed\n" if ( !$_ or $@ );
    }
    @scanners = grep{ $_ } @scanners;
}
# call the 'scan' routine in each module, and 
# print out the results from the array reference returned.
print @{&{$_}}, $/ for @scanners;
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And these two modules

package method1;
sub new{
    my $class = shift;

    return bless \&scan, $class;
}

sub scan{
    my @results = qw/foo bar baz/;
    #!do scan;
    return \@results;
}
1;
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method2.pm

package method2;
sub new{
    my $class = shift;

    return bless \&scan, $class;
}

sub scan{
    my @results = qw/the quick brown fox/;
    #!do scan;
    return \@results;
}
1;
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I get these results.

C:\test>209857
foobarbaz
thequickbrownfox

C:\test>
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which seems to indicate that the method works. However, whilst I cannot see anything wrong with the mechanism, it's the first time I tried anything like this so I am fully expecting to be told either that there is a much simpler way of doing this, or that there is something fundementally unsound in what I have done.