Okta at least can act as an SSO provider for Google accounts. I'm not sure how that's done, it seems a bit like black magic. As far as I'm aware Google Apps only allow you to log in with Google accounts otherwise.
Whoah, awesome! I guess I was always searching with the wrong terms :/, I did search for "federation" though FWIW. Maybe that's what I should have gone with instead of OpenID with Oidle.
Yup, although calling it black magic isn't far off from the truth. It's why I stick with oauth and let my coworker handle SAML. (They do SAML both directions, which is how we added it to AAD and Windows). It's a bit of a rough implementation though, so we can't do everything we'd like.
