If you have access to heavy truck brake drums, they make good grills. Just put legs on, and weld a few pegs on the inside and cut expanded metal to fit.
The tank from hot water heaters make good BBQ pits. I have one on legs that has wheels on one end, handles on the other end to pick up and move from place to place.
You have a talent for making useful scrap items, keep it up!
Rocket stoves are awesome! We had a small, very basic one and it was so lovely as back-up when we couldn't use our electric stove due to power failures.
You are correct. They don't produce much smoke because there is almost complete combustion. That means you are getting more bang for your buck. Smoke is basically unburnt combustible material. Since it's more efficient you end up using less wood to cook your food. Less heat is wasted. And they're easy to make and portable.