Hello ,
I have been looking into your requirement, however such a control is not in the immediate road map. As a substitute I can suggest you checking our XamTilesControl
which provides a window management lookalike functionality which is very user-friendly. If you need to indeed work with windows I can suggest you also check our XamDialogWindow.
If you have any additional question regarding those controls please submit them to the designated WPF forums. Thanks in advance.