purcforms…

Sounds promising…

This is GWT based form designer and form runtime engine. The form definitions are stored as xforms and the layout (position, size, etc) of input widgets (textboxes, buttons, etc) is stored in a custom XML format. One can use the form designer and form runtime engine separately. Incorporating any of the two in your application requires just referencing one JavaScript file and having a few other dependant files on your server. The form designer also has an html file that you can run in the browser without requiring a server.

URL: http://code.google.com/p/purcforms/

(thx Knut for the link)