Hey, yes it is possible to create such a shipping calculator. Infact, I have created one for some other client as well. The calculator I have created allows the client to enter shipping rates from multiple shippers (FedEX, UPS, HKPost, SwissPost etc.) and then based on country to which it needs to be shipped, the rates of different shippers are displayed.
Your requirement is at a Zip level. Right? So, if you have shipping rates for zips, I can create a 'lookup' method that will get the shipping cost based on zip entered.
Do let me know if you would like me to work on this project for you and we may discuss the details.
Thanks and Regards,
Shikha
(Automyze Consulting)