Yes, it is still around. We spent some time in Montreal around the New Years holiday, and it was still there.

For some reason, this (and the ones in Toronto and Boston) is one of my wife's and daughter's favorite places to eat in the world. We cannot hit one of those cities without eating at Marché multiple times.

We were at the Hong Kong Marché last June and I don't remember seeing anything about an all you can eat deal there. As bigguyinpasadena mentioned, the Montreal location doesn't have any all you can eat deals either.