@JonB, yes I have done that before from the ui. I think @ccc helped me getting it going. For the moment, I am working on my cell class that is used by the VirtualView. A part of the flexibility I wanted for the cell is to be able to load a pyui file as its view. I can get that working. But the bigger idea in my mind is just composing cells/views from multiple views, memory or file based. But to have those elements be in the same addressing space.
I can also see many times you would not want this. When you want the container view and its subviews to be a subview.
But I think times when you would like view merged into views (hierarchy flatted out).