Speed up Kohana ORM init

ORM.php

<?php defined('SYSPATH') or die('No direct script access.');

class Kohana_ORM extends Model implements serializable {
	
	/**
	 * Initialization storage for ORM models
	 * @var array
	 */
	protected static $_init_cache = array();

	/**
	 * Prepares the model database connection, determines the table name,
	 * and loads column information.
	 *
	 * @return void
	 */
	protected function _initialize()
	{
		// Set the object name and plural name
		$this->_object_name = strtolower(substr(get_class($this), 6));
		
		// Check if this model has already been initialized
		if ( ! $init = Arr::get(ORM::$_init_cache, $this->_object_name, FALSE))
		{
			$init = array(
				'_belongs_to' => array(),
				'_has_one'    => array(),
				'_has_many'   => array(),
			);
			
			// Set the object plural name if none predefined
			if ( ! isset($this->_object_plural))
			{
				$init['_object_plural'] = Inflector::plural($this->_object_name);
			}

			if ( ! $this->_errors_filename)
			{
				$init['_errors_filename'] = $this->_object_name;
			}

			if ( ! is_object($this->_db))
			{
				// Get database instance
				$init['_db'] = Database::instance($this->_db_group);
			}

			if (empty($this->_table_name))
			{
				// Table name is the same as the object name
				$init['_table_name'] = $this->_object_name;

				if ($this->_table_names_plural === TRUE)
				{
					// Make the table name plural
					$init['_table_name'] = Arr::get($init, '_object_plural', $this->_object_plural);
				}
			}
			
			$defaults = array();

			foreach ($this->_belongs_to as $alias => $details)
			{
				$defaults['model'] = $alias;
				$defaults['foreign_key'] = $alias.$this->_foreign_key_suffix;

				$init['_belongs_to'][$alias] = array_merge($defaults, $details);
			}

			foreach ($this->_has_one as $alias => $details)
			{
				$defaults['model'] = $alias;
				$defaults['foreign_key'] = $this->_object_name.$this->_foreign_key_suffix;

				$init['_has_one'][$alias] = array_merge($defaults, $details);
			}

			foreach ($this->_has_many as $alias => $details)
			{
				if ( ! isset($details['model']))
				{
					$defaults['model'] = Inflector::singular($alias);
				}
				
				$defaults['foreign_key'] = $this->_object_name.$this->_foreign_key_suffix;
				$defaults['through'] = NULL;
				
				if ( ! isset($details['far_key']))
				{
					$defaults['far_key'] = Inflector::singular($alias).$this->_foreign_key_suffix;
				}
				
				$init['_has_many'][$alias] = array_merge($defaults, $details);
			}
			
			ORM::$_init_cache[$this->_object_name] = $init;
		}
		
		foreach ($init as $property => $value)
		{
			$this->$property = $value;
		}
		
		// Load column information
		$this->reload_columns();

		// Clear initial model state
		$this->clear();
	}