This topic really interests me and has helped me to think out of the box... so to speak. I've tried the replacement LED bubls that fit in the stock location, but they are not bright enough and they trip my "check XXXX lamp" indicator on the message center.
I took out my R tail lamp and I think it would entirely possible to install them from the inside. This way, you could use white LED's which are cheaper and brighter, and the setup would use the stock reflectors to amplify the light. This also opens up the opportunity to cusomize the lights to make them work the way you want. You could (probably) wire them so they all work together or just install and wire them so they operate in the same manner as the stock lamps
But, I need to know some things about LED's to make this work... We need to have the LED's shine brighter for a directional signal and for a brake light. How is this done, by illuminating more LED's or is it by simply adding more current to the existing LED? I don't imagine they work like a dual fillament bulb. Anyone shed some light (pardon the pun) on how LED's work like this?
Also, how are the LED's installed. Can you simply drill through the back of the tail lamp housing the same diameter as the LED and afix them in place with some epoxy?
So, I drew up a quick image below of how I think this could work. The problem, as I stated above, is how to have the brake lights and directional lights shine brighter than just the parking lights. Also, the LED's for the parking lights have to be bright enough to see the car at night and in poor weather. And the brake / directional lights have to be much brighter than the parking lights to distinguish them as such.
Help yourself to comments and suggestions.