Great idea; but I would scale it down, or go to the Chevy dealer or the junk yard and get the 3rd brake light and housing for a Chevy Astro Van.Blended into the body it shouldn't be too bad. One option might be to get one of those "universal" hood scoops (the kind that are just for looks) and mount it backwards. Then place an LED light bar in the scoop vent.
They used one like the picture till 2005