package MyApp::DBConnection
use Moose;
has dbh => {
	is => 'ro'
};
sub BUILD {
	#load the config from a config file, etc.
	#create the connection, set the handle.  Etc, etc.
}

1;

package MyApp;
use Moose;

has dbConnection (is => 'ro', isa => 'MyApp::DBConnection', default => sub { MyApp::DBConnection->new() });
1;