I have a game which uses std::wstring as its basic string type in thousand of places as well as doing operations with wchar_t and its functions: wcsicmp() wcslen() vsprintf(
Try out CrystaX's NDK. It has had stl support long before the official google one. The current version (r5), which is based off the of the official ndk r5, is still beta 3, but it does have wchar_t support.