Are hallacas similar to tamales? If you'll settle for tamales, I'd recommend Columbus Bakery. Most tamales available around town will be home-made, or at least not commercially made.
2931 Dufferin, east side south of Lawrence
Also there are a lot of small vendors at the Latin plaza/mall near Finch and Weston. There is a thread here: http://chowhound.chow.com/topics/353358. There might be a Venezuelan one.
Good luck finding them!