Have you thought about using 4 LEDs on the ring around the rotary knob? Perhaps using smaller parts if the ones you've got on there now are too wide.

Seems like you've pretty much put together exactly what I was thinking back when some of the original lighting threads were going on.

Would you mind putting up any info on the mold-making techniques/products you've used? I looked briefly at some possible casting materials for making re-usable molds, but nothing in depth. Thinking about making the molds was driving me a bit batty without actually trying it though.

Bruno