Here's some shots of the taillights. They're side markers for trucks (i think i paid $3 each), i just ripped out the incandescent bulbs and glued in LED's. No optics at all, that way i get some side visibility on them. They're driven by a 5V power supply that i literally ripped (dremel cut) out of another electronics assembly. It's a switching power supply so again, fairly efficient. They're wire in series and use a current limiting resistor of 2.2ohms to limit the current to 300mA. I've heard people driving these at 600mA but the difference in brightness didn't seem worth it to me, i'd rather stick in more LED's and as you can see, i have the real estate to do that (later).