I have a number of US wall-warts (for various things) and they all have the US-style 2 parallel pins. They are all 100-240V so that is not the issue. And I don't want a collection of the Oz-US converter plugs.
So, does anyone know if such a thing is available in Oz?
They aren't, in 3 pin versions, and I have looked.
Unfortunately you have to buy them from the US - or from local specialist suppliers, as they are used INTERNALLY in US made commercial equipment such as some Jukeboxes, cinema and Bowling Alley machinery.
Note also that most of the black square USA panel mount inserts i have had experience with are pretty shit quality, they only contact the plug pin on one side, and the brass leaf that does this tends to break off, resulting in no power, or worse, possible arcing and a possible fire.
However if you want to make your own, the Clipsal No: 403 socket is a 2 pin version of the USA socket, and is readily available from Haymans. (note, this is UNEARTHED, and also it does NOT have the different sized active/neutral pins that are found in a normal USA style wall socket, so some USA plugs MAY NOT fit, unless you file down the larger of the 2 pins.) (for a plug (2 pin) clipsal have the #492 series)
IF you look in their catalogues, you will also find that you could order in an insert (that fits a standard clipsal/hpm (cant remember which) wall plate, and had 2 parallel US style pins. This was in the
1990's, it might not still be available.
I would advise the clipsal items, they will at least be rated at 240v whereas imported items probably won't.
What's wrong with purchasing Australian 220V/240V wall warts for your items? They're cheap, well sourced and many are just lying around in the bottom of boxes/drawers waiting to be utilised again. The AC/DC plugs really shouldn't be an issue either, because of their ready availability. You may even be able to pick up a few wall warts from the surplus bin of your local electronics shop, or even from a computer/electronics swap meet for a dollar or so.
20-30 years ago when every electronics shop carried the sockets, I simply made my own power boards. Not very difficult, and incorporating fuses, filters, surge protection, switches or anything else you desire is easy.