nashvillian, the country-specific settings have been taken over by the integration with Workflow-ng. You can see how Ãœbercart sets up the shipping quotes by default on the Workflow-ng page under Site building.

For your example, you would want to edit the configuration for the flatrate method. On the configuration's page you can see space for conditions and actions. It starts out with one action, which is to calculate a quote using flatrate. Quote actions shouldn't really be messed with.

What you want is to add a condition. There are many different conditions available, but we're interested in the order's delivery country. On the condition's setting form, the most important part is the country selection. Select both US and Canada and set the label to something informative like "Order ships to US or Canada". Submit the form, and you're done. Only orders going to US or Canada will see the flat rate quotes.

But we don't really want those orders to see the quotes by weight! The process is the same: add a condition to the weightquote configuration. The difference is that we want to click the "Negate" checkbox when we choose US and Canada. This means that orders NOT in US or CA will see the weightquote. Since an order will be in US or Canada or not, all orders will see one of those quotes and not the other. It's a good idea to make sure that every order you get is eligible for a shipping quote.

Conditions can be combined in all sorts of ways, so Workflow-ng should allow for any kind of business rule for shipping quotes and taxes. Discounts should be able to benefit from this soon, too.