Check these out;
http://www.americanbassusa.com/amps.html The HP series are pretty god for the $$. They have a 40x4 (does about 60x4 actually) and a 50x4 (75x4 real power as well) The largerr one has a variable xover (hp or lp filter), the smaller one has a fixed 80hz xover (hp or lp). Both are stable to 2 ohm stereo and can be bridged. They are full MOSFET amps are quite suprising when it comes to power. I can get the small one for $120 plus shipping and the larger one for $170 plus shipping. No sure what kind of warranty it has with it going to Canada, has full US warranty though.
