Montreal's new video scoreboard is huge. It was installed last summer (2008) by Daktronics, and the main screen is about 17' x 30'. (Even bigger than Vancouver's huge scoreboard, which measures 13' x 24'.) The video below gives you an idea of the scale - it drawfs the on-camera host. Also interesting in this vid are the photos of previous scoreboards in Montreal.
Yes, it's big, but nowhere near as big as the Kansas City Royals scoreboard (85'x105') or the forthcoming Dallas Cowboys scoreboard (71' x 159').