This company has just finished their Beta test and will be releasing their plugin next week: https://www.temando.com/
These guys are developing one now. It's in beta phase at the moment. They suggested I post a link to their site so you can register your interest and be notified when it's available -- which they say should be soon. http://courierquotes.com.au/wordpress/wordpress-shipping-calculator-australia/
I would also be interested in one.