Rename 'kohana' to 'system' to conform to the Kohana filesystem layout. I'm comfortable with us not clearly drawing the distinction about the fact that it's Kohana.

system/libraries/Model.php

@@ -0,0 +1,31 @@
+<?php defined('SYSPATH') OR die('No direct access allowed.');
+/**
+ * Model base class.
+ *
+ * $Id: Model.php 4007 2009-02-20 01:54:00Z jheathco $
+ *
+ * @package    Core
+ * @author     Kohana Team
+ * @copyright  (c) 2007-2009 Kohana Team
+ * @license    http://kohanaphp.com/license.html
+ */
+class Model_Core {
+
+	// Database object
+	protected $db = 'default';
+
+	/**
+	 * Loads the database instance, if the database is not already loaded.
+	 *
+	 * @return  void
+	 */
+	public function __construct()
+	{
+		if ( ! is_object($this->db))
+		{
+			// Load the default database
+			$this->db = Database::instance($this->db);
+		}
+	}
+
+} // End Model