[mattdawson]

> I can't imagine how I would construct a scene with a gold/white dress and then take a picture that looks like the one in the OP

I can. To me, this initially looked like a situation where the background is lit with incandescent bulbs with the dress being in sunlight. In a photo where you have parts of the scene that are lit with incandescent bulbs and other parts are lit with sunlight, correcting white balance for the incandescent part of the scene (yellow -> white) will make anything that's white in the sunlit part of the scene very blue. That's what I was seeing here.