International Shipping API PHP

We are looking to develop a shipping API to integrate into TT-Products and Typo3 environment for one international carrier (UPS or DHL) and (currently) one type of service that includes drop shipment calculation. Example: a customer in the US buys 3 products through our online shop that will be shipped from the US, France and the UK. The same must work for customers in Europe , asia, etc. The API must: a) calculate the shipping dynamically through the shippers API b) once the order is placed, notify the shippers and transmit required shipping information c) works with flat rate, weight, order total and per-item based shipping d) add handling/freight charges e) taxes and shipping fees based on customer's location f) tax exempt feature g) transmit the appropriate information to add to the package (invoice, etc) h) uses the harmonized 6 digit international shipping code There are several cart solutions out there that offer the basics, but not the international matrix and that is the most important aspect. I am sure some of you have existing parts that just need to be tweaked. We also need the backend solution for the API, that tracks the status of the order with the different shippers. Decision will mostly be based on examples of similar previous work done. Please do not bid unless a similar project has been worked on before. For any given site examples they must be bug free. I won’t be interested in your company if your portfolio site has bugs, it’s an indication to me of poor customer service and it says to me if you can’t debug your own example sites then I dont like to think how my programming bugs will be fixed...