Tremblant is truly insanely busy in the Xmas season, I heard they make half their money from the 25th of dec to Jan 2nd, and having been there once at that time I could believe it.
I just got an email from them with lodging deals that end on Dec 18th. My brother in law has a pass from there that allows him to ski at all times except over the xmas season. All signs point to few discounts at that time. However lift tickets look like they can be had for $50/day if you buy now from this link:
Latitude Card - The best discounts to ski Tremblant with no compromise! - Tremblant Ski
not sure about the $115, is that ski and stay?
latitutude card seems like the edge card at whistler, best way to go.