Big thumbs up to this forum for all the great information and inspiration
I scoured the pages upon pages of information, then set out on my own journey to build the ultimate backyard bbq beast.
Just a few notes that may be helpful to the next guy:
I have no welding skills or access to equipment -- and still ended up with a pretty decent fire box. I found the expanded metal at Orchard Supply in 12" x 24". Picked up two pieces and molded them around the ol' propane tank. Bolted the two ends together. Used the bottom bolts (about 2" from the edge) to serve as supports for the Weber Kettle coal grate. Added 2 additional bolts opposite of the seams to complete the support. This gave the coal grate 2" of lift from the bottom of the pizza pan / ash pan. The stainless steel carriage bolts lift the pizza pan about 1" from the bottom of the drum and secure the fire box to the ash pan. End result -- base of coals are about 3" off the bottom of the drum. Not shown is the wire basket handle I added. I fretted for a bit regarding the placement of the food grate. Lots of different opinions on distance from fire, etc.
I ended up just measuring about 7" down from the top of the drum and placing the grate there.
Once it was assembled, I built two fires in it just to burn it out and season it a bit. Then I gave it a go with some chicken quarters. I had it running about 225 - 250 depending on how I fiddled with the air flow.
I let the chicken go about 3.5 hrs -- internal temp about 160 degrees. Ended up super tender and juicy! I'm a convert!