I don't think there is any program like VS Windows.Forms for C++. Now I know that "Windows.Forms" are in themselves a C# "thing", but it eludes me why no one has put together a similar graphical construction interface for C++ Windows GUIs. Am I just not aware of it/them?
Should I try to make one (that'd be a challenge, for me anyway, but what fun!)? Anyone want to talk to me about making one with me?
Yes, you are just unaware. The one I'm most familiar with is for use with the Qt Toolkit: QtDesigner. I'm sure there are others as well...
I'm not entirely sure what you're after - the designer? The framework?
The closest to Windows Forms is probably MFC, although various other GUI framework also exist... and some of them are portable, such as Qt and GTK+.
EDIT: For the designer side, from the Wikipedia Visual Studio page:
For MFC development, it provides a set of wizards for creating and customizing MFC boilerplate code, and creating GUI applications using MFC. Visual C++ can also use the Visual Studio forms designer to design UI graphically.
Small correction: The Windows.Forms toolkit is not a C# specific toolkit, instead it's a .Net toolkit. Therefore it is available to versions of C++ which support managed code. Namely C++/CLI and C++ with managed extensions. It is even available to native C++ via COM interop and a lot of funky marshalling. But for raw native C++ with no managed components in the box, yes it's not available.
As to why? Probably because there are already several Windowing toolkits available out there for C++ which have a similar feature set as Windows.Forms. Here are a couple I know of
It's there, in Visual Studio, and has been there since before .NET, assuming you are talking about a graphical editor for laying out controls on a window. http://msdn.microsoft.com/en-us/library/6zd672xs.aspx