So, I started thinking ... I used 1 second exposures (G, B, anyway) for the original still dice images. To get the correct exposure, I had to set the camera to ISO 100 and the lens to f/22. The ISO will go up to 3200, and the lens opens to f/1.8 (I cannot justify buying the very nice Canon f/1.4 or the coveted f/1.2). At these settings, the camera is:

times as sensitive. I should be able to use 210 us flashes and get the same exposure! That should be fast enough to capture the dice in motion, even using lousy 1-chip 3W LEDs driven with a BJT and a resistor.

I have to get down to the bench now.

I think I can make a simple trigger with two pieces of aluminum foil that get pressed together by falling dice.