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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I think I will stick with tie for now:
• Performance is not an issue in this case
• Both of those are modules that use c/c++ and are not core
• I am keeping my deps at a minimum when possible because my module will bundle itself for other systems, the less I have to bundle the better, currently it is YAML::Syck and Getopt::Long only.
• This is a proof of concept, the class I am tying to in production does more

Both of those are modules that use c/c++ and are not core

That's a non-issue. Lexical::Alias is trivial to build using cpan and available via ppm for Windows.