If you can't find it, then you can always have someone make it for you. I prefer to use
qqcosplay because they've been pretty reliable. But you can also post
here in search of something a little more homegrown (support the economy and all).
For making your hair white, there's "white hairspray" which will give it that effect. It'll cake a little bit and be kinda flaky, but it's a pretty cheap choice. Personally, I prefer wigs, but Scar's hair is pretty short, so it might be difficult to find something comparable.
If you have any more questions, I would suggest dropping by
cosplay.com. The forums there are full of helpful people.