There are a million different ways to make ANYTHING blink. Perhaps the simplest solution is to build a single transistor oscilator circuit, but the output transitions tend to be soft and you can't load them that well. Your best bet might be to take a 555 and then drive a MOSFET or even a bipolar transistor which will switch your Luxeon circuit. /ubbthreads/images/graemlins/smile.gif
It would be easy to vary the on and off times, both can be done with variable resistors.