Policy editor? Gui?

Is anybody working on a open-source graphical policy editor ? 
Is there a business case for it?
What would be the minimum set of features to make it useful?
Should it be tailored for a particular implementation, such as SunXACML
or could it be useful for any XACML policy?

I've been thinking about editor ever since I had to write policies. It's
very inconvinient to edit them in regular XML editor. 

Thanks,
Argyn