Dassault Super Mirage G8A

[rickshaw]

The F-111 didn't enter Australian service until ten years after it was ordered.  If the Mirage G development had been ordered by the French government, it would probably have been available in a similar time frame.  It wouldn't be too unusual for a customer to pull out & wait longer for an aircraft that it felt better suited it's needs, the UK did exactly that when they cancelled orders for F-111 to develop the MRCA/Tornado.

True but the Australian Government had ordered it and paid for it.  You can pull out before you've put down the cheque but not after - without severe political repercussions.  As the then Liberal government had in part placed its reputation on the line in the what, 1963 election over the matter of a Canberra replacement (along with other defence re-equipment).

[Mossie]

Yeap, very costly, very stupid to commit for so long then throw things away & that was exactly the way the UK government did things! 

A change of Government would be one way in for the Mirage G.  I guess I'm going on UK politics here, but I could imagine an opposing political party simply shedding the F-111 in order to cast itself as the white knight.  A few shenigans, envelopes under tables & all that could also help swing things the G's way.

[GTX]

It would be quite feasible to pull out of the F-111 deal.  For one, they could claim they had been sold a 'lemon' and refuse to take delivery and probably get a refund - depends upon the exact nature of the contract.  They could also take delivery and then on-sell (let's say Pakistan or Iran ).  The option of the change of Govt could also be a good trigger - what if Dassault offered a very attractive deal - say in country license manufacture + the offer of exporting parts (as was the case in the real world with the Mirage F.1 offer).

anyway, this was just an option to help make the RAAF a long time Mirage user:

Mirage III
replaced by Mirage F.1 in the '70s + Mirage G (maybe with a few years of Mirage IV ops in the interim whilst pending delivery)
F.1s replaced by Mirage 2000s in '90s due to delay of Rafale...

Either way, I did prefix it by "What if ..."!

Regards,

Greg