I've never heard of them, but I'm not sure I'd like cooking with it, especially if you were cooking meat, you just wouldn't know when it's cooked thoroughly. Plus you could only use it in certain parts of Australia and only during certain times. Personally I couldn't trust it to cook the meat, and it would be very temperamental according to the sun. I'm not sure it would be worth it. Just my opinion.
Hopefully someone on here has had some experience with them.
not sure about how then are made these days, but when I have made and used the home made alfoil variety and it does take a long time to cook anything on it and it does depend on the sun. The cookers in the links in your post include some which are obviously commercially made, so could be worth a try but the common denominator is that they all need to reflect the heat from the sun. I remember cooking (or perhaps heating is more correct) a frankfurter with kids some years back using one made mainly from alfoil and a box. Good luck - would be interested to know how it goes for you.
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The Maccas ....
2013 Avida Esperance Motorhome - based in northern NSW.
I vaguely remember seeing something about bush cooking a roast with a cardboard box and alfoil. I'm pretty sure the inside of the box was lined with alfoil and not the outside (which would reflect heat away from the box). The alfoil on the inside was meant to keep the heat in. I think it took a couple of hours or so to cook a roast perfectly in hot sun. But don't quote me.