I have written a Windows OpenGL context creation for given HWND (initially for DGUI but it isn't a restriction, one just have to write his own control class) because of complicated context creation in this OS (~800 lines of D code for only context creation with desired parameters) and lack of functionality like: "here is my windows handle - create new context with it/use it with an existing one".
Including OpenGL 3+ contexts?
I don't think you are looking for such solution, so it is here just for information. But if someone need this, I will release sources.
Please do so, could be helpful.