Drag and drop online form editor with login(flash)

I'm looking for help to create the front-end of my project. This webapplication is going to be an easy way to create online forms where the forms are running in flash/air and can be edited in drag and drop style. In the form the superuser are able to add common controls such as; checkboxes, dropbox, radiobutton, textfield and calender and name then accordingly to what type of information they are collecting. The form is supposed to be saved by the superuser and access thru a different URL by the user(which can not edit the form). The superuser get access thru a secure login page. The security asepct is not part of the project, but the login page is. The superuser should also be able to add pictures/logo to top of the form. Not part of the front-end, just included here to give the context: When the user submits the form the information from the controls is collected by the backend system which runs in .NET so the frontend must be able to expose the data to the backend. Open for suggestions on this point.