I have two thirty five gallon stainless steel drums that are stoves for emergency use now. I put them in use back in the late seventies, worked wonderfully. One upstairs fireplace and one in basement fireplace, bought kits from a company named sotz, out of business now. You can buy good gasket material and good furnace cement to seal up the door frame etc.
I have heard of old transformers being used, old water heaters, big pipe casing, two hundred fifty gallon fuel tanks with two sets of doors etc.
"Younz" have a great day, I will.