We (Foxpass, https://www.foxpass.com/) are a YCS15 company offering a SaaS (or on-prem) service to handle SSH key management & rotation, plus user and group management.

With our API, some customers are creating dynamic access rules (for example, an on-caller might have 'sudo' during their on-call week, but not at other times).

Like a hosted FreeIPA, but more powerful.