You can make references to the variables instead. You'll have to do a little dereferencing in your print statement.

%hash = (
    key1 => \$foo, 
    key2 => \$bar, 
    key3 => \$baz, 
);

print "Bar: ${ $hash{key2} }\n";
$bar++;
print "Bar: ${ $hash{key3} }\n";
[download]

I've tested similar code on my machine.

----
I wanted to explore how Perl's closures can be manipulated, and ended up creating an object system by accident.
-- Schemer

Note: All code is untested, unless otherwise stated