Note: Data::Alias doesn't compile on Windows since it accesses private Perl internals (which the Window build process forbids) to make its powerful syntax possible. I just found Lexical::Alias which doesn't have that problem.

use Lexical::Alias qw( alias );

my ($ident, $value) = @_[0,1];
alias $_[1], $VALUES{ $ident );
$_[1] = $value if defined($value);
splice(@_, 0, 2);
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Update: It looks like Lexical::Alias can't alias a scalar to a hash element. It looks like you'll need to use tie as a fallback after all. Here's a slightly simpler version than what you had:

{
    package My::Tie::Scalar::Alias;

    use strict;
    use warnings;

    use Tie::Scalar qw( );

    our @ISA = 'Tie::Scalar';

    sub TIESCALAR {
        my ($class, $ref) = @_;
        return bless $ref, $class;
    }

    sub FETCH { my $self = shift; return $$self;  }
    sub STORE { my $self = shift; $$self = shift; }
}


tie $_[1], 'My::Tie::Scalar::Alias', \$VALUES{ $_[0] };
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