捆绑商品的价格定义在
app\code\core\Mage\Bundle\Model\Product\Price.php

通常我们使用函数 getTotalPrices() 来获取捆绑产品的价格

// 获取最大价格
$bundle_p = Mage::getModel('bundle/product_price')->getTotalPrices($product,'max',0);
// 获取最小价格
$bundle_p = Mage::getModel('bundle/product_price')->getTotalPrices($product,'min',0);

有的时候捆绑产品子产品会售罄，这时候捆绑产品的最大价格就是 除去售罄子产品后的子产品价格之和。
新的需求：
即使子产品售罄，但是捆绑产品最大价格也显示所有的总价格：
函数实现：

// 重写 core 文件 app\code\core\Mage\Bundle\Model\Product\Price.php
public function getAllSelectionsDisplayPrice($product, $which = null, $includeTax = null, $takeTierPrice = true)
{
    $finalPrice = $product->getFinalPrice();
    if ($product->getPriceType() == self::PRICE_TYPE_FIXED) {
        $minimalPrice = $maximalPrice = Mage::helper('tax')->getPrice($product, $finalPrice, $includeTax);
    } else { // PRICE_TYPE_DYNAMIC
        $minimalPrice = $maximalPrice = 0;
    }

    $product->getTypeInstance(true)
        ->setStoreFilter($product->getStoreId(), $product);

    $optionCollection = $product->getTypeInstance(true)
        ->getOptionsCollection($product);

    $selectionCollection = $product->getTypeInstance(true)
        ->getSelectionsCollection(
            $product->getTypeInstance(true)->getOptionsIds($product),
            $product
        );


    $options = $optionCollection->appendSelections($selectionCollection, false, true);
    $minPriceFounded = false;

    if ($options) {
        foreach ($options as $option) {
            /* @var $option Mage_Bundle_Model_Option */
            $selections = $option->getSelections();
            if ($selections) {
                $selectionMinimalPrices = array();
                $selectionMaximalPrices = array();

                foreach ($option->getSelections() as $selection) {
                    $qty = $selection->getSelectionQty();

                    $item = $product->getPriceType() == self::PRICE_TYPE_FIXED ? $product : $selection;

                    $selectionMinimalPrices[] = Mage::helper('tax')->getPrice(
                        $item,
                        $this->getSelectionFinalTotalPrice($product, $selection, 1, $qty, true, $takeTierPrice),
                        $includeTax
                    );
                    $selectionMaximalPrices[] = Mage::helper('tax')->getPrice(
                        $item,
                        $this->getSelectionFinalTotalPrice($product, $selection, 1, null, true, $takeTierPrice),
                        $includeTax
                    );
                }

                if (count($selectionMinimalPrices)) {
                    $selMinPrice = min($selectionMinimalPrices);
                    if ($option->getRequired()) {
                        $minimalPrice += $selMinPrice;
                        $minPriceFounded = true;
                    } elseif (true !== $minPriceFounded) {
                        $selMinPrice += $minimalPrice;
                        $minPriceFounded = (false === $minPriceFounded)
                            ? $selMinPrice
                            : min($minPriceFounded, $selMinPrice);
                    }

                    if ($option->isMultiSelection()) {
                        $maximalPrice += array_sum($selectionMaximalPrices);
                    } else {
                        $maximalPrice += max($selectionMaximalPrices);
                    }
                }
            }
        }
    }
    // condition is TRUE when all product options are NOT required
    if (!is_bool($minPriceFounded)) {
        $minimalPrice = $minPriceFounded;
    }

    $customOptions = $product->getOptions();
    if ($product->getPriceType() == self::PRICE_TYPE_FIXED && $customOptions) {
        foreach ($customOptions as $customOption) {
            /* @var $customOption Mage_Catalog_Model_Product_Option */
            $values = $customOption->getValues();
            if ($values) {
                $prices = array();
                foreach ($values as $value) {
                    /* @var $value Mage_Catalog_Model_Product_Option_Value */
                    $valuePrice = $value->getPrice(true);

                    $prices[] = $valuePrice;
                }
                if (count($prices)) {
                    if ($customOption->getIsRequire()) {
                        $minimalPrice += Mage::helper('tax')->getPrice($product, min($prices), $includeTax);
                    }

                    $multiTypes = array(
                        //Mage_Catalog_Model_Product_Option::OPTION_TYPE_DROP_DOWN,
                        Mage_Catalog_Model_Product_Option::OPTION_TYPE_CHECKBOX,
                        Mage_Catalog_Model_Product_Option::OPTION_TYPE_MULTIPLE
                    );

                    if (in_array($customOption->getType(), $multiTypes)) {
                        $maximalValue = array_sum($prices);
                    } else {
                        $maximalValue = max($prices);
                    }
                    $maximalPrice += Mage::helper('tax')->getPrice($product, $maximalValue, $includeTax);
                }
            } else {
                $valuePrice = $customOption->getPrice(true);

                if ($customOption->getIsRequire()) {
                    $minimalPrice += Mage::helper('tax')->getPrice($product, $valuePrice, $includeTax);
                }
                $maximalPrice += Mage::helper('tax')->getPrice($product, $valuePrice, $includeTax);
            }
        }
    }
    $this->_isPricesCalculatedByIndex = false;
    if ($which == 'max') {
        return $maximalPrice;
    } elseif ($which == 'min') {
        return $minimalPrice;
    }

    return array($minimalPrice, $maximalPrice);
}

此函数是参考 getTotalPrices 实现的，其中有代码：

$options = $this->getOptions($product);

这里会过滤掉售罄产品，而我们不想他被过滤。

public function getOptions($product)
{
    $product->getTypeInstance(true)
        ->setStoreFilter($product->getStoreId(), $product);

    $optionCollection = $product->getTypeInstance(true)
        ->getOptionsCollection($product);

    $selectionCollection = $product->getTypeInstance(true)
        ->getSelectionsCollection(
            $product->getTypeInstance(true)->getOptionsIds($product),
            $product
        );

    return $optionCollection->appendSelections($selectionCollection, false, false);
}

其中 appendSelections() 函数参数可以配置哪些子产品被添加：

public function appendSelections($selectionsCollection, $stripBefore = false, $appendAll = true)
    {
        if ($stripBefore) {
            $this->_stripSelections();
        }

        if (!$this->_selectionsAppended) {
            foreach ($selectionsCollection->getItems() as $key => $_selection) {
                if ($_option = $this->getItemById($_selection->getOptionId())) {
                    if ($appendAll || ($_selection->isSalable() && !$_selection->getRequiredOptions())) {
                        $_selection->setOption($_option);
                        $_option->addSelection($_selection);
                    } else {
                        $selectionsCollection->removeItemByKey($key);
                    }
                }
            }
            $this->_selectionsAppended = true;
        }

        return $this->getItems();
    }

可以看到最简单的 设置参数 $appendAll 为 true 即可。
所以修改方式就是，修改了 options 的获取方式。

$options = $optionCollection->appendSelections($selectionCollection, false, true);

后面的限制：

if (!$selection->isSalable()) {
    /**
     * @todo CatalogInventory Show out of stock Products
     */
    continue;
}

删除即可。