As you know, users of the "Google.CA" interface get the option of seeing results only from sites Google thinks are "from" Canada.

Google's various methods for determining this seem to get tweaked over time, but I've found that the use of a '.CA' domain trumps the IP geo-location ... which may be Google's first-pass factor.

All domains we've hosted on U.S.-based servers have been reported as being "from" Canada when we've employed that TLD.

(These domain also often have .COM incarnations.)

Steve