Assuming you don't have any multi-valued CGI parameters, I'd probably do something like this:

#!/usr/bin/perl -w
use strict;

use CGI qw(param url);

my $me = url;

my %params;
my @params = param;

$params{$_} = param($_) foreach @params;

my @value = qw(AAA BBB CCC DDD);

foreach my $v (@value) {
  foreach my $p (0 .. $#params) {
    print "$me?".
           join '&',
                 map { "$params[$_]=" . 
                       ($p == $_ ? $v : $params{$params[$_]}) }
                      0 .. $#params;
    print "\n";
  }
  print "\n";
}
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--
<http://www.dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg