How would this idea work in an International scenario?
Our website crosses borders, and we actively ship from the USA to 28 countries, and it's a substantial percentage of our business.
Our products range from small, cheap widgets to heavy, expensive widgets. It's not uncommon for the cost of international shipping to exceed the cost of the widgets.
Your ideas are great for intra-country shipping, but how do you implement this, without knowing the ship-to address of the visitor?