I know there have been a lot of discussion on this topic but id like to share this product that I stumble in Japan. I believe they have a distributer in the US as well.

It lets you run several configuration between Campagnolo 'ULTRA SHIFTER" 10 or 11 speed to shimano Der/cassette/chain.
A friend of mine is running 10 speed set up.
I am running the 11 speed set up. I just finish installing mine and will be ready for a ride in a day..
Initial impression is, it has a decent shift quality.. I am using old shimano drivetrain with a good amount of miles. I suspect things can be better with a new chain and a good cleaning.

reason for doing this: I ran Campy on my road bikes and wanted to do the same on my cross- bike with wider gear range . I am currently running 11-36 cassette

Below is the link. It is a Japanese site and you might need google chrome to translate.

https://growtac.com/products/eq-pulley/