To tell you the truth I never heard of the Onix Rocket UFW-10, but after some research the reviews were very very good, it's always mentioned they are "musical" which is exactly what I'm looking for. There was one review done which I cannot find now but the reviewer stacked it up against SVS, HSU and Velodyne and he was blown away by the Rocket UFW-10. But now I have heard of them and one is on the way :) and it's just the right size..
http://www.hometheaterhifi.com/volume_11_2/onix-ufw-10-subwoofer-5-2004.html
http://www.goodsound.com/equipment/rocket_ufw_10.htm
http://www.hometheaterhifi.com/volume_11_2/onix-ufw-10-subwoofer-5-2004.html
http://www.goodsound.com/equipment/rocket_ufw_10.htm