It seems the Netbeans-Forte effort has inspired IBM's developers. They promote Eclipse which is their new tool platform and have built Websphere studio workbench on it. Amongst Eclipse's design goals are the IDE modularity (plug in based) and consistent look an feel (and behaviour) with the underlying platform it's running on.
They have developed a new set of GUI widgets called SWT (Standard Widget Toolkit) which act as an adapter layer to the native platform widget libraries. If no native widget is available on the platform, it's emulated. The result is pretty amazing. You end up with a java applications looking like the latest Office suite on the Windows Platforms.
A community has been formed on www.eclipse.org. Notice that you have to apply for an account at www.developer.ibm.com to be able to download the latest builds of the IDE.