can you do HTML/C# , or HTML/C++ , or XAML/Javascript in Windows 8 Metro?
I know that i could have a HTML/JS that could include a WinRT .winMD “DLL” that happens to be C# or C++ and call it from the JS, but is there any other way?
Also i presume that i could make a WinMD Dll containing Javascript functions and call it from a XAML/C# or XAML/C++ but are these the only ways?
Not all combinations are allowed in the 3×3 matrix of language/rendering technology.
You can create Win RT components using C++ or .NET (C#/VB) but not JavaScript. You can use those components from a JavaScript app as well as a .NET or C++ app.
See documentation for creating C#/VB modules here.