Apparently this was mentioned at the Flash Forward conference. A snippet from Christian Cantrell's blog:
Meet "Royale" (codename), a new way to generate Flash user interfaces using XML. Neil Balthaser did a demo from the office of a credit card form that automatically does validation which he build with just a few lines of XML. More on Macromedia Royale to come.
I don't know about you, but this sounds very sexy. I like Flash. I love Flash Remoting. ActionScript is pretty darn cool as well. I hate having to lay out my interface. It's such a waste of time. If this would make that step of developing a RIA go away, I'd adopt it in a second (and develop a lot more Flash apps).