Huh, that's pretty neat. Problem is you'd need the engine and the rest of your car to be able to position it effectively as well, though I guess you could probably just use the mounting pad on it and references to your hoop to get it close.
Your hoop looks pretty similar to what I ended up with as well. I didn't go quite as form fitting as I had limited ability to bend stuff beyond a vise and hammer though.
The other option is to be silly like me and buy a 3D scanner yourself, lol. I had all sorts of ideas when I bought it, but in practice it doesn't work out quite as nicely as I would have liked. I think it would actually be great for something like the transmission with a lot of detail on it, or larger stuff like an engine bay. The big problem is then turning those scans into something useful for CAD. Millions of tiny points stitched together into surfaces makes for huge files, plus they don't necessarily have an easy origin point to pick from or measurements, so they are really most useful for stuff like clearance checks or making block models off of. It's also just not super mobile to use since it wants a pretty beefy computer to run it.