We have a powerful java based platform which aim at building enterprise applications with requirements like yours. The sigificant character of it is that it can produce user interface, service components and related configuration files automatically. Morever, it can create three kinds of presentation form simultaneously, of which java desktop (typically used by admin) is one, web flex is another, and HTML+JS is another. It means you can have three kinds of application. If we do the project, besides application, platform would be delivered as well. You can benfit from it during the phase of maintenance.