Custom Shipping Overwrite - PHP and MySQL + Bonus

I am in need of someone that can allow for another field to show up in the product input page that points to the database. This should be for shipping prices, and this price should overwrite any other default shipping options arleady setup. For example if I am inputting product X into the backend and on the form next to it I input the shipping cost of $27.95, than everytime someone orders product X it should automatically charge them $27.95 regardless of other shipping rules. This form on the input part should automatically override. If nothing is put into the field it would go back to the default shipping settings. Of course after you input information into the field from the backend it would go right into the the MySQL database just like all of the other fields. So I am in need of someone to create this function on the product input page, while also tieing this information to the database and setting it up to overwrite the default settings if information is put in. I need this completed within 5 days, and I want to pay no more than $150. A bonus of $50 will be given to someone that can complete this in the given time frame. Thank you for your bid.