Last weekend, I let her paint (with her watercolors, no less) an old 2nd ed Berserker. It actually looks kind of awesome.
I would imagine that watercolors would do pretty well over a white primered mini, they would probably act a lot like washes. She could have the first all-pastel khorne army.
Give a man fire, and you keep him warm for a night.
Set a man on fire, and you keep him warm for the rest of his life.