There is another possibility, likely the one I'd pick if I wanted to do this. I'd repurpose my Chuff-Generator to output the signals. It reads the tach strip, thus certainly knowing exactly what speed the motor is going, and it has two FET outputs that can support plenty of current to manage the lights, and a couple more PIC processor pins that could drive a flickering LED with no problem. It's so much easier to do stuff like this if you have a little intelligence in the circuit.
