Magento – Configurable products showing out of stock in magento

Create your own module, and in the config.xml file add these 2 events inside the tag:

<events>
    <controller_action_layout_render_before_catalog_product_view>
        <observers>
            <namespace_module>
                <class>module/observer</class>
                <method>showOutOfStock</method>
            </namespace_module>
        </observers>
    </controller_action_layout_render_before_catalog_product_view>
    <controller_action_layout_render_before_checkout_cart_configure>
        <observers>
            <namespace_module>
                <class>module/observer</class>
                <method>showOutOfStock</method>
            </namespace_module>
        </observers>
    </controller_action_layout_render_before_checkout_cart_configure>
</events>

Now create an observer inside app/code/local/Namespace/Module/Model/Observer.php

class Namespace_Module_Model_Observer {
    public function showOutOfStock($observer){
        Mage::helper('catalog/product')->setSkipSaleableCheck(true);
    }
}

Here is a script with which you can find all those configurables that do not have simples with stock. Afterwards you could then use that array of Ids to exclude them in your filter.

<?php
require_once('app/Mage.php');
umask(0);
Mage::app();

$collectionConfigurable = Mage::getResourceModel('catalog/product_collection')->addAttributeToFilter('type_id', array('eq' => 'configurable'));

$outOfStockConfis = array();
foreach ($collectionConfigurable as $_configurableproduct) {
    $product = Mage::getModel('catalog/product')->load($_configurableproduct->getId());
    if (!$product->getData('is_salable')) {
       $outOfStockConfis[] = $product->getId();
    }
}

Then use this to remove the configurable products which are not saleable from your collection:

$products->addAttributeToFilter('entity_id',array('nin' => $outOfStockConfis));