Some news from us at UpdraftPlus - we're gearing up to replace the Clef plugin based on exactly the same idea:

https://updraftplus.com/clef-user-updraftplus-now-gearing-replace/

UpdraftPlus is one of only six commercial plugin companies in the world (including Automattic, Yoast and until recently Clef) that maintains a plugin with more than 1 million installs.

We're calling it "Keyy" and hope to launch in April. The plugin is already finished - just finishing the apps.