| Assuming that this light would fit nicely on your tank and all that, it does sound like a pretty good price for the unit. I was looking at light upgrades last night and saw a similar 6 bulb system for about 200 dollars more than this one.
Of course, you will be sort of ahead in the game since you are going to build your own canopy and if I were you, I might think about incorporating a little ledge in it to hold the lights up off of the water slightly and maybe ensure that there is some sort of clear plastic (not easy to melt plastic, of course) barrier between the lights and the water. I have noticed that SW seems to 'jump' on the surface a bit more than FW and so you would want to protect this unit.
I have a canopy on my tank, but it is a factory made one. It has an open back and I can remove the tops if I want to or need to in order to allow heat to escape. My lights also have built in fans, but in the summer time I am thinking I will have to add a few more to deal with the heat outside of the tank as well as inside. I think fans are going to be a real neccessity for you but you should be able to go to a computer store (or maybe a goodwill or second hand store) to get yourself some of those little fans that cool PC components. (Maybe you can pick up some old, used computers at a second hand store and just take out the fans) I am thinking about getting myself four of them and attaching them to the sides of my canopy. Even though they are small, they do work well and I can feel the heat that they move. Having the plastic barrier between your lights and water will also help you make your fans more efficient. Maybe glass tops would be a consideration as well since they can help reduce evaporation, but they seem to trap heat into the water on my tank. I also use the same description as the seller explains about how to use the three plugs to simulate dawn, dusk, and daylight for you fish and this works well and reduces the heat generated by the lights since all of the bulbs will not be on at one time throughout the whole day. | 
T-5 fixture on Ebay. Please look and give thoughts ASAP. Thank you. 
