SpiderOak has been prototyping an end-to-end encrypted and collaborative note-taking app for some time, with an anticipated launch in 2017. If you're interested, signup below for announcements and be eligible for two months of upgraded service when the product goes live.
We anticipate general pricing to be competitive with Evernote's current plans but built with the same secure, Zero Knowledge messaging technology used by SpiderOak in Semaphor, with reviewed and published source code.