There are several already. In my opinion, the best...

# datascience

[altavir]

There are several already. In my opinion, the best is http://beakerx.com. It features not only the notebook kernel, but also visualization for JVM, other jvm languages and transfering data from JVM to python and back. It needs some help to migrate to KEEP-75 right now: https://github.com/twosigma/beakerx/issues/7898