Smallest reef capable fixture

[Elvis48]

I've got a small "Ocean Treasures Collection - Bottom Time" fish tank that I'm trying to do a nano reef with. I've got a very tight space to work with as far as fitting something inside the top/hood of it is concerned. It comes with a small florescent light fixture, but the bulbs seem to get the tank too hot. I was searching for led solutions, to maybe dissipate heat better but have had no luck finding anything that will likely fit/work. I've got about a 6x6x4 inch area to work with. The only thing I've found so far is from aqualumination.com, but it is very expensive and has a fan for cooling, which I'm sure will be an issue under the hood for this tank (just like the bulb). Does any one know of any small reef capable led solutions with external power drivers I that could run wires and mount outside the tank? Or, do you have any other suggestions lighting wise? Thanks