What you did not test is the global hash:

              Rate   anonhash globalhash    ternary
anonhash   32323/s         --       -59%       -63%
globalhash 79642/s       146%         --        -8%
ternary    86652/s       168%         9%         --

With only a few more entries the global hash would be faster. However you have to name each of these global hashes (and I am bad with names).

#!/usr/bin/perl

use strict;
use Benchmark qw(:all);

our $hash = {
  foo => "results for foo",
  bar => "results for bar",
  qaz => "results for qaz",
};
sub globalhash
{
    my ( $x ) = @_;
    $hash->{$x} || "... and so on, ad nauseum";
}
sub anonhash
{
    my ( $x ) = @_;
    { foo => "results for foo",
      bar => "results for bar",
      qaz => "results for qaz",
    }->{$x} || "... and so on, ad nauseum";
}
sub ternary
{
    my ( $x ) = @_;
    return ( $x eq 'foo' ) ? "results for foo" :
           ( $x eq 'bar' ) ? "results for bar" :
           ( $x eq 'qaz' ) ? "results for qaz" : 
           " ... and so on, ad nauseum";
}
my @strings = qw/foo bar baz qaz/;
my $i = 0;
cmpthese( -5, {
                anonhash => sub { anonhash( $strings[$i++] );
                                  $i = 0 if ( $i == @strings ) },
                ternary => sub { ternary( $strings[$i++] );
                                 $i = 0 if ( $i == @strings ) },
                globalhash => sub { globalhash( $strings[$i++] );
                                  $i = 0 if ( $i == @strings ) },
               } );
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