OpenXava is a tool for Rapid Java Web Development, well-suited for business and database oriented applications. Since v4.2 OpenXava also produces iPad Web applications that behaves and looks like iPad native applications.
OpenXava allows you develop applications just by writing simple domain classes with Java or Groovy. The user interface is generated automatically in runtime, without code generation.
When the user access to an OpenXava application from an iPad a special suited user interface is generated, including the visual style of all UI element, layout and even native effects like slide and flip.

See the demos, or learn more in

Are native iPad applications practical to be used as enterprise applications? What do you think?
Do you think that current web application "as is" are confortable from an iPad?