I bought the one I have now from
www.reefgeek.com, but payed a little too much after shipping and everything to use him again. I have found a couple of places in Canada that also sell them now:
http://www.reefperfection.com/cat393_1.htm
http://www.aquariumobsessed.com/
But these are the only two I have come across (and Aquarium Obsessed onle carries the 250W version).