One of our favorite makers, Maurice Ribble, who is the mind behind the wonderful CameraAxe high speed photography system just released what I think is the first in the world (or at least in the last 10 years) to-the-masses AirGap flash.
An AirGap strobe works differently than your typical hot shoe or monoblock. Your typical strobe ignites a Xenon bulb with about 300 volts of power. An AirGap strobe pours 16,000 volts into an air filled tube (yup, good old simple air).
So why would you want to use an AirGap flash? mostly because its light burst is super short. A regular strobe (at low power setting) will shoot a burst of light lasting about 1/25,000 of a second. This means that a bullet traveling at 1000 feet / second will be smeared over 1.4 inches. An AirGap flash pop will last 1/1,000,000 of a second practically freezing the bullet in mid air. Here is a comparison using a few different kinds of strobes trying to freeze a bullet mid air.