IDK if this is what you're talking about , but this fella shows ya how to make a 1' X 1' X 6" basket for an offset smoker. It does not appear to be hard to do. Ya might have to adjust the measurements to get the fit ya want.
A guy over at another forum made these out of 10 gauge ventilated 304 stainless. No drilling necessary as the holes line up perfectly to accept a 1/4" bolt.