This is the very question I have had recently. There is getting Kandy paint from an auto paint store, but it's about $80 a quart and probably not the same thing.
I did a little more digging after I posted this last night. I found some videos of guys doing it with airbrushes on their motorcycle parts (fenders, gas tanks, etc) and a few on actual helmets with rattle cans. One guy used DubpliColor Metal Flakes™ and a bunch of laquer spray. Amazon has those for about $10/e. That might be an ok place to start if you don't have an air brush (I don't have one)
Would still like to hear if anyone's done this before.
This is the very question I have had recently. There is getting Kandy paint from an auto paint store, but it's about $80 a quart and probably not the same thing.
So I looked into it some more myself. I believe they are called "Glitter helmets." From what I have seen you apply glitter to a paintjob and clear over it. That's what I'm going to do anyway. here is a vid I found on it: https://www.youtube.com/watch?v=Yp4obbbMTZE