I've got all my metal together to make me a "rib pit" specific for smoking ribs. Basically like what your image is but with a fire box on the side. I had an old pit built like that and it made the best ribs. Just have to get a welder (my brothers portable gen/welder bit the dirt) but right now my toy money is going to a new Catrike 5.5.9 since my wife "stole" my Road after she took it for a test ride.
For me, it's only REAL BBQ if it's cooked with lump charcoal/hickory (or mesquite, or apple, or cherry or pecan). Some people have good luck with the LP/electric smokers but I never have.