Hmmm....do you know if by color matching acrylic paint with a person's skin tone if you can fake thinner brows? I get that foundation won't work over top, but I consider myself pretty good with color matching; I think I could get a color quite close to their skin tone and be able to blend the rest in with powder.
A couple guys from my cosplay group are cosplaying *extremely* girly guys and have thicker brows, and I doubt either one of them want to do something quite so permanent as plucking (which isn't permanent, I KNOW, but the amount of plucking that would be required is kinda excessive). I've kinda taken it upon myself to do their makeup to get them looking as convincing as possible, but I'd like it to be removable.
In Progress: Queen Beryl (La Reconquista, flashback armor)
Star Wars Celebration (no costumes though)