I've blogged a few times in the past about John Torjo's Win32 GUI Generics. It was really quite an impressive accomplishment using the advanced C++ techniques in Windows development, but was a bit of a rough diamond. I did do some minor changes to my local copy when I was playing around with it to make sure that the widgets used the correct Windows theming engine, and it was surprisingly easy to add which is a testament to the quality of the code. It did take ages to compile though with all those templates.
I notice that now John Torjo has posted eGUI++ to his blog. Hopefully this is a progression using all he learnt with his previous iteration in Win32 GUI Generics.
There is an article about eGUI++ on the MSDN here written by John. It covers the basics of what he has done and covers some of the features. It is typesafe at compile time which is great for catching errors early as most GUI toolkits you rarely find those types of problems until runtime (especially when using Windows resources).
You can download it from here. The example presented on that page is quick and to the point. Hopefully this is a toolkit to watch.