I wrote a free .NET implementation on Lua.
It does not use any C function so it should be easily portable. Even on Windows Phone / RT.
http://github.com/frabert/NetLua
Unfortunately, it seems still quite slow... I have tried running the Life example shipped with LuaWindows and I would say NetLua is DEFINETELY slower. Not gonna lie on that. It's only 2 weeks old, though!