The good news is that a new crop of Cloud-based Identity Providers has come up to solve the problem. They range from Microsoft Azure Directory Services, to Amazon's version, to Okta which extends the enterprise Active Directory (or other LDAP services) to the cloud, to One Login, which bills itself as an SSO for SaaS. It's exciting to watch this non-trivial problem being solved in creative and innovative ways.
A service that we've been working on (*association disclaimer) aims to not only provide SSO for SaaS, but also to unify the authentication policies across all SaaS services, as well as help finance folks manage the seat-based cost of SaaS is KoalaSSO. Sign up for Beta if you are considering moving your IDP infrastructure into the cloud and/or facing the user management across SaaS challenge.
A service that we've been working on (*association disclaimer) aims to not only provide SSO for SaaS, but also to unify the authentication policies across all SaaS services, as well as help finance folks manage the seat-based cost of SaaS is KoalaSSO. Sign up for Beta if you are considering moving your IDP infrastructure into the cloud and/or facing the user management across SaaS challenge.