package DBIx::Handy::Singleton;
our @ISA = ('DBIx::Handy');

my %instances = ();

sub new{
    die "ack! Cant call new on Singleton class '$_[0]'!\n";
}

sub get_instance
{
    my $class = ref $_[0] || $_[0];
    unless($instances{$class}){
        my $dbh = bless DBIx::Handy->new( $class->configure() ), $class;
        $dbh->connect();
        # ...etc
        $instances{$class} = $dbh;
    }
    return $instances{$class};
}

sub configure{ 
    die "Unimplemented abstract method 'configure' in '$_[0]'\n"; 
}

package MyApp::Foo; 
our @ISA = ('DBIx::Handy::Singleton');
sub configure{ 
    return (driver => ..., database => ..., ...); 
}

package MyApp::Bar; 
our @ISA = ('DBIx::Handy::Singleton');
sub configure{ 
    return (driver => ..., database => ..., ...); 
}