It's a good idea. I've been involved in the open hardware community for about 7 years now, the last 5 owning an open hardware based fabrication company. For you guys looking just to get something on the cheap this isn't the project for you. Designing and building open hardware is more than just looking to get something on the cheap. It's a process and until it gets past the first several iterations and becomes more mature it's not for end users but early adopters. For guys like Benchy and Steve, this isn't for them. These sorts of projects are for people that want to tinker and experiment and do their own thing.
Actually, exactly my kind of thing normally, but as I said more as an interesting project than a way to flll a real need on the cheap. I have always been the tinkerer. In the 70s I was building tuned-port speaker enclosures and passive crossovers making circuit boards with essentially a crayon and etching solution, then graduating to active multi-amp crossovers and double-sided boards using transfer sheets instead of wax pencils.
Anyway, other than that I agree with your post and the ones that followed.
And Shapiros is racer-friendly. Not the absolute cheapest but a great place to walk around picking through cut offs, scaps, etc and pay cash by the pound. Been doing that since I made my own sway bars for a 1969 Datsun 510, in 1975.