I have a 9 y/o (as of March 31st this year) FB grey who looks almost entirely white until you get up close and see he's got some fleabitten freckles on his face and neck. I've only seen one photo of him a bit younger under saddle but he looked nearly completely white then too! I guess he must have lost his color pretty early!
My palomino gelding was born completely chestnut then shedded out to an almost cremelo light pally and now is a nice yellow gold palomino who can get very dark gold during the summer.