A Kickstarter project is seeking funding to create the fastest camera flash, able to create a light flash of just 2 millionth of a second. A speed that makes it possible to freeze a bullet in the photo, see the photo taken with this system.
The project is developed by Vela Labs and is using LEDs as illuminator. A prototype version is available, and it has been used to take the photo shown here.
Of course what you also need is a very fast trigger, that works in the microseconds rather than milliseconds as we are used today. And Vela Labs is providing that too, at a cost of 2$ (whilst the flash is likely to be offered at a cost comparable to the one of a good digital camera flash, in the order of 400$).
Notice that the trigger is for the flash, not for the shutter! At this level of speeds you cannot think of activating a the shutter. What you do is to open the shutter and then use the flash to illuminate the sensor with the object reflected light. And this, in turns, require that you take the photo in an ambient that is completely dark so that no light, but the one produced by the flash, can hit the sensor.