Under availability, article says:
Motorola signature 27 will be available in markets worldwide in the coming months, with a starting MSRP of $1,599. For local price information and availability, please contact your local PR team.
... and while we expected a Canadian release soon, Motorola is now saying that the device will be exclusive to the U.S. with no availability in Canada at this time.
It definitely isn't US exclusive. We aren't sure when it will launch in each country and don't have a list. We'd be quite surprised if it didn't launch in Canada though.
Taking a device across the border shouldn't be difficult though, if you really want one.