I had written an interactive quiz application in Flash 8 years ago. It was pretty darned robust in ActionScript 2.0, and virtually impossible to port to ActionScript 3.0 without a complete rewrite, and abandonment of the timeline as an animation tool.
Have any of you moved on to something else? I would like the ability to run movie clips with embedded alpha layers, handle key presses and mouse clicks, and do simple moves and zooms of blocks of text.
In your question you’re looking for a new toolkit, which implies a full rebuild. So I would just suggest considering flash as the rebuild tool, since it has the features you want, and I don’t know of any other tool that has stage, movieclips etc and the IDE tool for animation. I hope you find a good solve.
You might also like some tools like Stencyl that are similar in some ways to flash (it publishes to flash) but has a visual programming interface.
http://www.stencyl.com/
For windows and Xbox there is XNA studio
http://www.microsoft.com/download/en/details.aspx?id=23714
and of course and interactive quiz is possible to be written in any programming language, including javascript or python among countless others.