Widget containers and groups - application builder

We are in the process of modifying the application builder to use our implementation of flex viewer and some extra widgets we have created. We are just at the process now of extending the functionality to allow widgets to be placed in side groups and containers as this seems to be something that is missing from the current builder.

Before we go to far down this line is this something that anybody has already done? Or is it something the flex team are looking at doing (Bjorn)?

Regards

Anthony