Been getting emails from Campagnolo on their new 12 speed cluster- wild, the chain must be super thin. Really the limiting factor is the chain, you can stack an awful lot of gears in a tight space.
I’m still running Campy Record 10 and haven’t felt a need to upgrade.
https://12speed.campagnolo.com/WW/en
Website isn’t fully working yet, they’re building suspense.