Vladimir Ralev from JBoss / RedHat has just check-in a new panel for the IzPack Java installer.

It acts like the classical packs panels but it can display the packs as trees. It will also report the required disk space sizes accordingly. I have included the following screenshots that Vladimir had sent to the developers mailing-list before getting the green flag for the merge:

You can test it now by checking out the latest version of IzPack from the trunk at http://svn.berlios.de/svnroot/repos/izpack/izpack-src/ or see http://izpack.org/developers if you need further instructions.