You could use the Zone Rates zones and set the settings as:
Zone 1: US, CA
Rates: 100:4.95

Zone 2: 00
Rates: 10000,14.95

What the 00 does is indicate any Zone not already defined ...

Then, to make the US look a little nicer on the Free Shipping on the Modules ... Order Totals ... Shipping ot_shipping ... you can enable the Free Shipping amount 100.00 and set to National, assuming you are in the US ...

The US would then see the Free Shipping on over $100.00 ...

Canada would see Free Shipping on over $100.00, but on the Zone Rate Shipping module ...