Possible at a pinch, the flyback I was using right there was about the size of a walnut. You could lay most of it out flat with the voltage multiplier and encase the whole thing in epoxy for (ha) safety.

I really wanted to go much higher with the voltages, but the amount of noise this thing puts out de-focuses the camera.

You could fit one into a portable hard drive case, though. Presumably along with an electric motor to make the appropriate noises when whoever you really don't like tries to plug it into their laptop.