Audio Warehouse use to carry the new line of Cerwin Vegas. Those were monster size speaker that I'm sure would rock with your 4B sst/2. I didn't see them there last I was there.
They carry Boston and Focal now. London Drugs carries Klispch. Future Shop carries Polk and Velodyne subs. Krazy Kiley's, Paradigm and maybe Ikon which looked like a good rock speaker.