I can't find any dual voltage LEDs, and actually is that how the break lights work? Like 6v for lows and 12 for hi power? If so, we could use the same LEDs for hi/low, because LEDs don't need full voltage to light up. For example; if you supply a 12v LED with 6v it'll still light up but it should just be dimmer. Now the problem is, is the dimmer half power LED too dim to be seen at night? Another option is to get two rows of LEDs, one row for running lights and one row for breaks/blinkers. Just get different output LEDs for each row. I'm gonna talk to a friend who helps me out with all my LED projects and see if he can't help out. I'll keep you posted.