You could use eCart to create a shopping cart that calculates the Shipping based on percentages, or even different percentages for different products or product groups
in eCart you could set a column for product category, for products that should changed the 15 percent rate, set that column to 1 and products that should be charged the 17 percent rate, set that column 2.
in the eCart object, create shipping rules using the Items with a specific column value option for the trigger and the calculation to determine which rule to apply.
we don't have a pre built shopping cart available that would do this though.