尝试

 <action method="setProductsCount"><count>5</count></action>

见/app/code/core/Mage/Catalog/Block/Product/New.php

See /app/code/core/Mage/Catalog/Block/Product/New.php

/**
 * Set how much product should be displayed at once.
 *
 * @param $count
 * @return Mage_Catalog_Block_Product_New
 */
public function setProductsCount($count)
{
    $this->_productsCount = $count;
    return $this;
}

阅读更多@http://www.magentocommerce.com/wiki/groups/248/display_products_on_home_page