Create Magento extension for XML feed

Hi, Please ready the requirements very carefully. It will save us both a lot of time I need a Magento Extension that will export my products catalogue to an xml feed. My requirements are: 1. The procedure must be fast. I will have 4.000 products in my catalogue and I need the xml to be created in less than 30 seconds. You will probably need to access the database directly. I have already tried a modification of the Daisyconfeed but it was too slow and it was exhausting my server's resources. 2. I will consider an "on the fly" creation of the XML as well as a manual or cron scheduled 3. The fields I need to be exported are: ID = The unique id of the product Name = The name of the product Link = The link to the product (e.g. [login to view URL]) Image = The link to the main product image Category = The category path of the product (e.g. TV/ FLAT/ PLASMA) Price = The price of the product 4. About the price field. My search engine only accepts 1 field for price. In my magento installation some products use the special price field. The extension must check which price is used on each product and set the "Price" field of the xml to the relevant magento price field. 5. About the Category field As I have said the Category field must hold the category path for each product (e.g. TV/ FLAT/ PLASMA). For the majority of the products in my store only the low level category is selected (e.g. PLASMA). The extension must identify must get the parent categories, up to the top level. The extension must check not to upload products that are not enabled, out of stock, or products with price <=0 6. The extension must be delivered to me as a zip file that I can upload via ftp to my server. 7. You are welcome to modify any other existing extension, as long as it meets the above requirements. Thanks for looking.