I will give a complete update soon but yes, CS has a kit that they make up to replace as each of the firebox walls that get damaged. I spoke with Tony and he was fantastic about the whole thing.
I do not do a lot of high temp grilling -- I would say averaged over a year I grill twice a week with sustained higest temps in the 450 - 500 range (only long enough to sear steaks so were talking 4-8mins at that temp.) I probably smoke items 1.5 times per month averaged over a year, but those are never more than 250 degrees, and often much lower for fish.
Evidently it is not an uncommon issue. From what I was told, even with their high quality stainless, the temps affect the structure of the metal and it breaks down causing this to happen.
The flame tamer bar you asked about that sat on the brackets lasted about 2/3rds as long as the brackets before it collapsed in half, and that is taking on the direct flame.
Once I get my repair kit I will post what the repair kit is like with a pic.