Well I am in the fortunate position of having a brother-in-law that works for a steel company that sources the aluminium for me. He cut and bent it to size and shape allowing me to slide a perspex sheet onto two "brackets" to act as a splash shield. This splash shield also reduces corrosion on the solder/contact points. This has been running for about 6 months without any corrosion showing up. The only issue I had last week was that one of the solder points disconnected but that's from the metal expanding and contracting with the winter cold.
This sheet covers a 600x500 area over my 1300x600x700 tank. It is mounted on an aluminium frame (built from mazey's connect-it system) and hangs about 20cm from the water level. I have two heat sinks and one fan and the temperature stays barely above room temp.
In your case I'd go an look at the heatsinks that Mantech (Mantech.co.za) sells. If you run them across your current setup with a fan or two you won't have any issues. You can buy the perspex in sheets from Builders Warehouse and you can use heat resistant silicone to stick the LED's down. None of mine have come off yet - it also helps convecting the heat to the metal to keep things cool.
I run 40x3w LED's and I actually think its too much...my corals seem happier with just 2/3's of them on. I also run more royal blue LEDs than white, but I think switching to a 50/50 split will be better so I might be changing them out soon.
This entire setup cost about R1500.00 if I remember correctly.