[Akaahn]

Sounds like VeraCrypt would be a perfect fit for you. Not sure if it supports Touch ID, but pretty sure it ticks all other boxes.

https://www.veracrypt.fr/en/Home.html

[atombender]

Thanks. The ergonomics of VeraCrypt don't seem to be much different from a sparsebundle, though. And I don't see how I could sync one to multiple devices.