Proposal for OpenCart guys

loader.php

<?php

// ...

public function model($model, $data = array()) {
		// $this->event->trigger('pre/model/' . str_replace('/', '.', (string)$model), $data);

		$model = str_replace('../', '', (string)$model);

        /* <custom_model_support> */
        $mod_file = DIR_MODIFICATION . ((defined('HTTP_CATALOG')) ? 'admin' : 'catalog') . '/model/' . $model . '.php';
        /* </custom_model_support> */

		$file = DIR_APPLICATION . 'model/' . $model . '.php';
		$class = 'Model' . preg_replace('/[^a-zA-Z0-9]/', '', $model);

		if (file_exists($file)) {
			include_once(modification($file));

			$this->registry->set('model_' . str_replace('/', '_', $model), new $class($this->registry));

        /* <custom_model_support> */
        } elseif (file_exists($mod_file)) {
		    include_once($mod_file);

			$this->registry->set('model_' . str_replace('/', '_', $model), new $class($this->registry));
			/* </custom_model_support> */
		} else {
			trigger_error('Error: Could not load model ' . $file . '!');
			exit();
		}

		// $this->event->trigger('post/model/' . str_replace('/', '.', (string)$model), $output);
	}
	
	
// ...