For some definition of "better":

my %hash = do {
    my @key   = $input->value_names();
    (@key, $input->possible_values())[ map { $_ => $_ + @key } 0 .. $#
+key ]
};
[download]

It has bugged me many times that there's no native way to "weave" two arrays in Perl. (Maybe there's an idea for a List::Util addition..)