Here we are going to turn 3 cheap ($4 each at fry's marketplace) LED screw-in lights into a fishtank light/hood combo.
Step 1: Break lamps
Step 2: Design your led layout in Illustrator
Step 3: Mark out sheet metal, drill holes.
mark out your led layout using sharpie and ruler.
drill holes - make sure you measure the led's diameter - not the wider lip part, but the thinner part. that way they will sit nicely in drilled holes and not fall through. my led's measurement was 4mm, or about 0.15" inch which is just over an eighth of an inch.
this is what your drill bit should be. if you don't have one this size, you can do smaller holes like i had to then gouge them out using knife to be perfect size, so when you poke led through it is snug, and won't fall through.
lay dow sheet and after snipping off leds from base circuit bend their connectors 90°.