As for the possibilities, check out Dominus's ArrayHashMonster.

UPDATE: sample code!

use strict;
use ArrayHashMonster;

my %hash; 
my @arry = (0..4);
@hash{('A'..'E')} = @arry;

my $monster = ArrayHashMonster->new(
   sub {$arry[$_[0]]},
   sub {$hash{$_[0]}},
);

print $monster->[3],"\n";
print $monster->{D},"\n";
[download]

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)