CC has posted a draft CC BY-NC-SA version 4.0 unported licence for public comment. The draft licence and a table comparing its terms with the CC BY-NC-SA 3.0 unported licence are available on this CC Wiki page.
Members of the public are most welcome to post comments and suggestions about the latest draft on the CC 4.0 Sandbox wiki.
As always, CC Australia will be keeping a close eye on this space.
You can read more about version 4.0 in CC’s announcement here.