Wes - I'm glad to see this build thread alive this long. That is indeed a piece of art!
I have a few questions:
1. What is the current dimensions inside the firebox (including height) and smoke box respectively? h x w x d
2. You mentioned you'd increase the inner dimensions somewhat... to what final dimension?
3. What is the outer dimensions of the smoker?
4. I believe you mentioned that your footer was 15' x 5' correct?
5. Because the heat in the smoke box should never be extreme, wouldn't 60% solid concrete block suffice? It does have a 2 hr fire rating which would easily get through the initial warm up period. IOW, does it need to be completely lined with firebrick?
6. Also, for some reason I'm not seeing how the air/ash clean-out channel fits into the overall design. particularly where it enters the firebox.
I'm a complete novice where masonry is concerned. I do have a 120" x 33" footer poured, and great desire for this smoker/grill dream to come to life though. My plans at this point are to block it out and wrap with cultured stone (wife likes the look better...and I know that the real magic is on the inside).