Anyway I've taken this off topic a bit...My bad
The fact is that the BBL will not move, and I doubt it will shorten. CA want it to be on every night, and rightly so. I would like to have more weekend double headers, but that won't shorten the season all that much anyway...I genuinely feel like the fix is simple.
Start the Shield in September. The JLT Cup started on Sept 16th this year, no real reason the Shield can't start then instead. This will, IMO, also help the batsmen develop; early season weather, greener, fresher wickets, more ball movement are all good things. That's also exactly a month before the Shield started this year (October 16th), which gives plenty of time to fit in the four games per side that are currently tacked on in March. Have the final the week before the BBL beings, in late December. This way you're playing at least the first three tests with players still playing Shield cricket recently, and there's a good lead in for the Test players to play a good chunk of Shield cricket.
BBL from late December as it is now.
JLT Cup in Feb/March to finish the season, running roughly alongside the international short form cricket...again, players can come from ODD cricket to ODI cricket if we need to make changes in the international side. Shorten it as well, play games more often
Beyond that, though, there are greater scheduling changes that will make a huge difference
-Use the Futures League better. Lengthen the competition and keep it running through the BBL. This is going to help in two ways; obviously, guys who aren't in the BBL can go back to a better quality competition than grade cricket, but it also gives more grade cricketers a chance to step up in place of some of the guys who might be in the BBL and play Futures League, have a stepping stone to potential state honours against state and Test level players.
-A tours. We need more of them, simple as that. We should be sending sides to the subcontinent and England and NZ and South Africa quite regularly. Give the next generation plenty of experience in all conditions, and use it to grow the game somewhat back home too. No reason we couldn't host Ireland/Afghanistan for some ODIs, some T20s, a one off test (on top of the main summer series) and three A side four day games for eg. You could run the A games early in the year, say January, into an ODI and T20 series in Feb and then a one off Test to finish the season at a smaller ground, Manuka or Bellerive or Dalton Park...
-Use County Cricket. We really should be putting as many blokes in County cricket as we can, and we should be trying to schedule our own matches so that we can. Obviously there are quotas and so forth, but there is no reason we couldn't have a chunk of a Test side over there any given year. The IPL is all well and good, but I would try and incentivise playing a season in County cricket here and there too. We should be supporting players who want to better their long form cricket more than the guys who head off to the IPL.
-Not so much a scheduling issue, but Grade cricket needs to be sorted out. Greg Chappell did a huge amount of damage to Australian cricket, and we need to sort it out and get the experienced heads sticking around in Grade cricket. That will go a long way towards helping young players develop their games