Mmm nice idea but would be very expensive i think. I built my Hotrod exhaust system from 316 stainless and a hell of a job. Twin system of course. I used mandrel bends from the steel headers, which are none too cheap either. S/S tends to crack also under very high heat and of course, goes blue too.
I think the mild steel and ceramic coated is the way to go. You need to find a exhaust shop with a mandrel bender which is not too common. Or buy a bunch of bends which is what i did when i fitted the Toyota

DOHC engine to my old white GT and weld them up. Tedious to do and even worse to do many of them especially after you watch a shop doing it with a machine.
If a set could be used as a dummy and a jig made from it, a shop should be able to make as many as needed and a spare or two.
BCCV might look at it maybe ?
glenn