More yellow knock-off type cases, of various sizes, are available from Autobarn...refer their catalouge. They are more expensive but meh!...cheaper than the real thing.
I don't know if it's nation wide..but they appear available in VIC.
Small.. 210 x 167 x 90mm $39
Med...330 x 280 x 120 $69
large...430 x 380 x 154 $89
Safe case...515 x 415 x 200 $129