I've been eyeing these for quite some time now:
They have many different styles and beam patterns available. Internal ballast, waterproof, etc. If it can survive the vibration and elements seen by motorcycles, i reckon it'd be fine for a car.
You can even get any color filter to cover the glass.
IMO it's a good bang for your buck, but you havent really mentioned how much light you want. Those trailtechs would be way brighter than the oem option, but may be overkill for your needs (not that cheap either).
what's the diameter of that placeholder piece?