There is a signficant advantage to stainless, it's nearly completely resistant to corrosion (depending on grade, obviously.) I made a charcoal tray bottom for my old grill out of a piece of stainless expanded sheet. That lasted for 3 or 4 years before the rest of the grill fell apart around it (I still have the sheet in the garage.)
The bars are not 90 degree bends, something more like 110 ish. Plus the cuts are usually on a angle other than 90 degrees. And a hole drilled in the bars towards the ends. I don’t know why this is. I would think protecting the burner tubes and providing some surface area to deflect and burn the drippings should be easy enough to do.
That said, I did look at purchasing pre-bent stock at maximum length with dimensions that would cover east-west 13 bar and 5 bar grills and I would cut them to length The retail stock price still wouldn’t beat an aftermarket bar set on Amazon back before the pandemic
Flavorizer bars are just 90 degree Vs, right?
Personally, I'd figure out how much I need, buy a partial sheet, and have a local machine shop shear pieces and run them through a press brake. I'll bet it'd take him about an hour for all of the machine work. Yes, I know.... most people just don't have the tooling or know somebody locally to do this.
