I assume you've already made the rounds of the various Belgian-beer-focused beer bars around town (La Trappe, Monk's Kettle, Trappist)? I know Trappist had a carbonnade on their menu a few months ago, but no idea if it's still there - never got around to trying it.
Rendez-Vous in Albany does a decent moules-frites, but it's a French place so no carbonnade. I didn't think their daube had much depth of flavor, so it's probably just as well. (I have a great recipe though, if you want to go over to the home cooking board.)