I think I have successfully use Qt for this "experimental" Illustrator CS6 plugin. I can create and show a Qt window that is triggered by Illustrator. So far, there is no issue. except that I don't use QApplication::exec().

Read EmptyPanelPlugin.cpp for the way I implemented it.

Some resources you might want to use:

• Getting Started with Adobe Illustrator CS6 Development
• [Scriptographer] (https://github.com/scriptographer/scriptographer)
• [Ai2Canvas] (https://github.com/mikeswanson/Ai2Canvas)