Honestly to me, it looks white. >< The angle of light on her in most of the pictures I've seen puts most of her hair in shadow but the highlights and brights are always a white. I think it would be neat if you got a white wig and maybe did a little marker dying with like a 20 or 30% grey (very light and subtle) at the roots and maybe a little on the ends.
Cosplay by a Left-Handed Ginger
Blizzcon 2009 -- Blood elf in Lovely Black Dress (World of Warcraft)
Blizzcon 2010 -- Illidan Stormrage, post-op (WoW)
Blizzcon 2011 - Day 2 -- Female barbarian, medium armor/concept art (Diablo III)
Phoenix & SDCC 2012 -- Eldon Ax (Star Wars: Fatal Alliance)
Blizzcon 2013 - Day 1 -- Akama, post-op (World of Warcraft)
Blizzcon 2013 - Day 2 -- Darkmoon Rabbit (World of Warcraft)