Shouldn't be too difficult, measure the brake light and get a local friendly sign writer to cut the letters out of his thickest black vinyl.
Alternatively get stick on letters and use them to mask off the light and then give it a good few coats of paint.
Not quite... I have a circuit board with the LED's all working from a 12-14V supply, but I need to find a good way to enclose it in a box other than one made from fosters cases covered in PVA glue
Getting there, just a question of experimentation!
