I haven't really considered that but I do have a sheild that somewhat blocks the heat of the bulb from the vho's. I but it on the tank last night and with the 2 fans mounted above the lights and I have another small fan blowing air in to the hood it was surprising cool. It actually runs my tank cooler with the new setup than the pc's I had on there before. I will let you know if it becomes a problem.
As for how much work it was it was actually not that hard. You got to remember I work in a sheetmetal shop so we have all the tools. Stainless steel is very hard to cut and drill. I tried to find some mirror finish aluminum but could not find any. That would of made it alot easier.