Aussie Diffs in Currumbin have them on their website for the Hilux at $990. That's Detroit Lockers, not Truetracs
I don't have their reply anymore, but I'm pretty sure that Locked Drive Systems in NSW were under $1000 also. You could also try Harrops in Victoria - don't recall their price.
There may be others, but I agree with you that $1450 is ridiculous. That's the sort of price you could perhaps have expected years ago when the A$ was around 60c/70c