After the Stats showed me, that the ancient Post about a Web based ZFS Interfaces produces a lot attention, i decided to restart with that project from scratch.
You can find the current sources here. I am currently working with the FreeBSD ZFS Version (so basically FreeNAS), but there are already some Test-Cases for Nexenta.
The basic idea of the system is, to use remote SSH Sessions for accessing the different systems and parse the receiving data. There is already a quite stable, JNA based Java Binding for ZFS, but it seems to be broken for the latest Versions of ZFS. And to have a simple solution to manage ZFS on different system, seems to me a great idea.
I have some ideas how to do some things, but it still seems a lot of work :-).