Have you checked out TIBCO's AJAX IDE and Framework?
The IDE is itself an ajax app that runs in the browser. Yep—a full
AJAX IDE for building AJAX apps.
InfoWorld just gave it the highest rating of all products in its class.
http://www.infoworld.com/Tibco_General_Interface/product_70328.html?
view=0&curNodeId=0
8 minute webcast: http://weblog.infoworld.com/udell/2005/05/25.html
You can download it and try it out from http://developer.tibco.com
--Kevin