Ok, this is most definately a quick hack, but it does work. I tweaked with the formatting of the output to match the structure of what you are looking for given the format of the data you supplied. Obviously, you will need to figure out the formatting for different data. (note the extra @reps data structure is required for output formatting purposes).

#!/usr/bin/perl
use strict;
my ($p, $r, $v);
my (%data, %products, %reps, @reps);

#iterate over data and store in hash
while(<DATA>) {
    chomp($_);
    ($r, $p, $v) = split(" ", $_);
    $data{$p}->{$r} = $v;
    $products{$p} = 1;
    $reps{$r} = 1;
    @reps = sort keys %reps;
}

# start formatting output
print " " x 10;
foreach (sort keys %reps) {
    print "$_", " " x 4;
}
print "\n";

#iterate over products
foreach (sort keys %products) {
    print "$_";
    # iterate over products
    for( my $i = 0; $i < scalar @reps; $i++) {
        # see if rep has that product and print if it does
        if( exists($data{$_}->{$reps[$i]}) ) {
            print " " x 3, " " x ($i * 8), " $data{$_}->{$reps[$i]}";
        }
    }
    print "\n";
}

exit;

__DATA__
rep1 product1 2
rep1 product2 2
rep2 product3 3
rep3 product4 4
rep3 product5 5
[download]

output:

155.~/perl/tmp > ./am.pl
          rep1    rep2    rep3
product1    2
product2    2
product3            3
product4                    4
product5                    5
[download]

hope this helps,

davidj