An excellent PCB from www.bigclive.com that is designed to fit into a standard 150W halogen floodlight case. It can either accommodate 18 each of red, green and blue superflux LEDs (3 or 5mm lens) for colour mixing with RGB controllers, or 54 of one colour.
Other applications include low energy (solar) lighting, vehicle lighting, emergency lighting, outdoor lighting or Hydroponic red/blue grow lights.
An all green version looks fantastic for spooky halloween FX!