Arda is based in Chicago and they are awesome. They recently previewed a new wig style that they say would be easily styled for Elsa. It has a built-in widow's peak and comes in their Silver colour, which is very close to white. Alternatively, Titanium Blonde is also a debut colour. The wig won't be available until December, though.
RIP CosRevo, Love Laugh, Sweety Pop, Cocosilver.