ocean aquatics carrys them i'm pretty sure, call wendell and check to see whats in stock, i'm guessing you got the long narrow 48'' 55 gallon right?
http://oceanaquatics.com/store/produ...-Bulb-Fixture/
did you ever consider metal halide though, they can be made to look great if you're into some dyi, they can be made into some very decent fixtures.