Thinking the same thing...
I know of nothing as yet, but talk of an Adelaide series is getting more serious. I know of at least two bike shops a that are keen to get things happening. There was talk of something at the Melrose Fat Tyre festival this year but nothing eventuated, but it might be worth keeping an eye on this year. It's been very hard to get anything started as so few Aussies have even spectated at a CX event, let alone organised one. The rules about permissable bikes is difficult to as so few people have true CX bikes, and most that are sold seem to be used as commuters/ light tourers rather than as muddy paddock machines.
Does anyone know from overseas experience where a good resource for official rules and useful course designs are available? Beach/sand based courses have me interested as that would work where I am year round. In SA we actually have had mud this year, but other years mud can be a hard to find resource.