Not sure if this fits the bill, but it might be of interest nonetheless

package Filter::ObfuMethods;

use Exporter::Tidy
  default => [ 'filter' ];

use Crypt::Rot13;

use vars '%methods';

sub filter {
  my $code = pop;

  my(@calls) = $code =~ m{ \$? \w+ \s* -> \s* (\w+) }gx;

  @methods{map crypt_method($_), @calls} = @calls;

  $code =~ s{ ( \$? \w+ \s* -> \s* ) $methods{$_} }
            ($1\${\\\$Filter::ObfuMethods::methods{"$_"}})gx
    for keys %methods;

  return $code;
}

sub crypt_method {
  my $c = Crypt::Rot13->new;
  $c->charge(shift);
  return $c->rot13(6);

}

q[the end];
[download]

And some code

use Filter::ObfuMethods;

my $code = <<'CODE';
sub foo { print "in foo\n" }
sub bar { print "in bar\n" }

main->foo;
main -> bar();

my $o = bless [];

$o->foo();
$o -> bar;
CODE

print filter($code);

eval filter($code);

warn "ack - $@" if $@;

__output__

sub foo { print "in foo\n" }
sub bar { print "in bar\n" }

main->${\$Filter::ObfuMethods::methods{"luu"}};
main -> ${\$Filter::ObfuMethods::methods{"hgx"}}();

my $o = bless [];

$o->${\$Filter::ObfuMethods::methods{"luu"}}();
$o -> ${\$Filter::ObfuMethods::methods{"hgx"}};
in foo
in bar
in foo
in bar
[download]

Ok, it's not terrifically obfuscated (rot13 not being the most secure of obfuscation methods) but it's something ;) It also needs to have more rigorous regex matching if it's going to be used on any old code and probably not delivered in it's current form and many other tweaks besides.
HTH

_________
broquaint