Here is a small cad drawing i did of the flush mounts and how they would need to be. Not shure on the dimensions cuz my car is about 80 miles away from me. I would make them out of either sheet metal and cut it then fold it, or even weld the pieces. You could either paint them black, mach the car or even polish them for a brighter look. For the covers I would have a small 1/4 in lip around the top edge and attach aome high quality plexiglass, lexas or acrilic to it. And just cuz im on the topic, you could also get a film to go over the glass to make them light up certain colors or yellow like lemans cars. Either window tint or you can but the film made for headlights.