What kind of rim does it have? Is there a center brace? You might like to get two separate fixtures that fit into the lip created by the top rim and the center brace, with glass tops to control evaporation and splashing. Measure the space on each side and look for fixtures that length.
I am really enjoying the Current USA Satellite fixture I recently purchased, as it has integral moon lights that are so cool in the dark, and the PC
lighting is great. This fixture has half actinic, which shows off the colors of fish so much better than the typical PC
lighting I have for plants. This is not a planted tank so I could experiment a little. They are similar to Coralife but WAY cheaper. This is where I got mine http://marineandreef.com/shoppro/power_satellite.html