Mission will have all of last years gear at 40% off as well and the taxes in alberta are only 5% and empire will charge shipping.
Source should have some good deals as well.
Wiredsport.com ships to canada but its flat rate shipping so just to buy bindings is not always worth it. another site is valuesports i think. there is a thread in the board section that talks about usa shipping to canada.
i doubt the big 3 is worth it as i don't know anyone that rides at norquay. however i have never ridden there so i don't know personally. norquay does have night riding.
Sunshine has the best snow and the longest season of all the mountains in banff. there are some cat tracks to manage. Lousie has the best park and steeper terrain in banff. Sunshine is only 1 to 1.5 hours while louise is 2 hours for sure.