Hey, Chuck, for the velocity stacks.. What about taking a trapezoid-ish shaped piece of sheetmetal and wrapping it around your form the tig'n it up? As long as theres no absolute necessity for it to be all one piece, functionally, I see no difference. And after dressing and polishing you probably wouldn't 'see' a difference either. I know its ghetto, but I thought the original criteria was 'CHEAP'.
When the place I used to be with was making these, we had the inner and outer stacks CNC'd, but it was big money.
Believe it or not these twinstacks kicked ass for a while, and put a couple bikes to the top of their class.