I was speaking to a Hammer/Felder rep yesterday on the phone, and he said that most of the times, when machinery is not available in Canada versus being available in the US, it is because of UL versus CSA reasons. Seems the standards/requirements in Canada are different and/or higher.
As far as I know, Festool has never given a reason why the Carvex intro was pulled for NA, but it may be because they would not be allowed to sell in Canada, and they simply will only offer a tool in NA if it is available in both countries. Hey, it's a bit of a shot in the dark, but I've not heard of a better explanation/guess as to why we still don't have the Carvex.