anyone ever get a headlight ticket?
I don't think lower than 24" would be a big issue as long as you are close to that. But LED bulbs in a halogen housing is a bad idea. You will have a ton of super bright light out to about 50 feet, and then nothing. It won't be focused, and you will be able to out drive the lights, along with blinding oncoming traffic. Similar to all the Chevy guys in my area that put HID light conversions in their halogen housing and it's like staring at the sun when they are coming towards you.
Take a look at
RetroShop Custom Lighting or
Welcome to the store for lights that might work. They have LED housings that might work if you are going custom anyway.