Yep, there has been a bit of discussion about the MPL on D & G as well as other threads.
Yes, CASA is currently developing a syllabus for such a licence in Australia in conjunction with ICAO and Alteon (sp?) is working on the same.
What interests me is whether the MPL is going to be airline specific? In other words, will someone with an MPL be restricted to the airline whose syllabus they followed in getting their licence? My cynical mind suggests that some airlines would favour that approach.