No, haven't got around to doing the tail sign yet - and what I found in terms of an image is not a patch on what you have! I'd have to do it in plastic - no metalworking skills - but I have learned to use metal finish paints that can produce a good facsimile of the real thing.
I can help more on the tail sign illumination. Basically I have found that multiple smaller LEDS, say 4 or even 2, are better than one LED of any significant size. A 3 mm will LED throw a lot of light out but in a straight beam so you end up with a hot spot in the sign. Plus you will get reflected light bouncing back behind the LED so it has to be sealed off from the interior. A single incandescent bulb of roughly the same size as a 3 mm LED will spread the light better but they burn out and replacement is a big deal unless you have built your interior to accommodate that.
I also tried disc-shaped flat LEDS but they only come in larger sizes and the light is really too intense for this purpose.
