That design looks pretty nice and simple- I like! Aluminium will melt fairly readily at campfire temps. Be careful how much heat you really put in there.
We frequently melt our beer cans into aluminium ingots in steel cans, as well as melting whole aluminium sand stakes that appear to be the same thickness as the pan. I'm not saying the pan will melt the first time you use it, just that the kayakers I know would melt it their first time out.
The exact same design could be executed with steel parts. Heavier- same pan should be about 20lbs, rather than 8, by my calculations. Of course, you could probably get away with a lighter gauge for steel than Al, so that might cut that ~20lb number a bit more. Either way, split among several paddlers shouldn't be too bad, if you want to have anything hotter than, say, 30 charcoal briquettes.