Dynamically add items to admin menu in Magento

config.xml

<?xml version="1.0"?>
<config>

    ...
    
    <adminhtml>
        <events>
            <controller_action_layout_render_before>
                <observers>
                    <module_update_admin_menu>
                        <class>My_Module_Model_Observer</class>
                        <method>updateAdminMenu</method>
                    </module_update_admin_menu>
                </observers>
            </controller_action_layout_render_before>
        </events>
        <menu>
            <MAIN_MENU_ITEM>
                <children>
                    <MENU_ITEMS_CONTAINER translate="title" module="module">
                        <title>Menu Items Container title</title>
                        <sort_order>1000</sort_order>
                        <children>
                          <!-- Children are added dynamically -->
                        </children>
                    </MENU_ITEMS_CONTAINER>
                </children>
            </MAIN_MENU_ITEM>
        </menu>
    </adminhtml>
    
    ...
    
</config>

Observer.php

<?php
class My_Module_Model_Observer {

	/**
	 * Update admin menu with dynamic items
	 */
	public function updateAdminMenu()
	{
		$menu = Mage::getSingleton('admin/config')->getAdminhtmlConfig()->getNode('menu/MAIN_MENU_ITEM/children/MENU_ITEMS_CONTAINER/children');

    		// Repeat numbered steps below as many times as you want to add items to the admin menu

    		// 1. Create $xml which is a valid admin menu item definition
		$xml = '<dynamic_item><title>Dynamic Item</title><sort_order>10</sort_order><action>adminhtml/some/route</action></dynamic_item>';

    		// 2. Make a config node with $xml content
		$node = new Mage_Core_Model_Config_Element($xml);
		
		// 3. Append $node to existing loaded menu node
		$menu->appendChild($node);
	}
}