https://aapjwp-0h.myshopify.com/en/products/stiffshifter?variant=56090872185180
Curious idea and I have mixed feelings.
Reinforcing a mech hanger reduces the chance of it doing what a mech hanger is supposed to do.
On the other hand, I agree that the length of the mech and the size of the cassette does put a greater bending moment through the mech hanger
I’d seen these advertised, but hadn’t read about them and the stiffness claims. I think eightpins are the sister company of liteville and syntace. I used to have a similar idea on my 301. No idea about stiffness claims, but it seemed to offer some protection to the dropout. (Never broke a dropout in 10yrs with that bike) Granted it was frame mounted that axle mounted.
These first came into existence in the early 2000s - they screwed onto the QR axle (remember how easy they were?) instead of the regular nut. They weren't popular then and sort of disappeared when through axles took over.
I remember them first time around. But a big cassette back then was 34T. Mech stiffness was less of an issue.