Welp, here's the final design. I'll give a basic rundown of the construction, but it's actually not too terrible complicated. Everything I used besides the thermometer, the colander, the gasket, and the J-B Stik putty can be purchased at Home Depot.
Major parts include:
2 19" Ceramic Cobalt Blue Pickle Pots
1 15" Weber replacement grill
1 Ceramic saucer
1 9" granite colander
8 1/2" black steel nipples
8 1/2" black steel caps
2 8" black steel 1/2" pipes
2 1/2" black steel 90* angle joints
2 1/2" brass ball valves
1 Pit Thermometer
~5' high-temp gasket
4 1/4" x 3" bolts / nuts / lockwashers
Drilled four holes in the pot with masonry drill bits and placed the bolts through them to hold the grate. Used J-B Stick putty to seal in the steel nipples and pipes w/ ball valves to the drainage holes for intake/exhaust.
The 9" Colander serves as the charcoal pit. Cut 1/4" steel bar into four 14" segments, used J-B Stik to bond together for a platform to hold the wood plate.
And of course, the finished product. Forgive the UPC labels I hadn't taken off yet.