Nice! I really like what you did!
I have been thinking hard on what to do for lighting on a 125 6' long I am working on. To start I was just going to stick a 48" fixture that I currently have above it (2x actinic 2xHQI), but was thinking to build something very similar to what you have here.
I keep going back and forth between 3x250w halide pendants with 4x T5HO or a full T5HO only setup like yours.
If you don't mind and if it isn't trouble, can you PM me a list of parts you used? Pics and/or construction info? I may just build one!