Once you have your Drupal site configured as a Shibboleth/SAML Identity Provider (IdP), you can configure Dataverse to authenticate against it as explained in the guide above.
With regard to the "experimental" status of Shibboleth support in Dataverse, I have a pull request at
https://github.com/IQSS/dataverse/pull/3025 that fixes some mostly minor bugs that I imagine will land in Dataverse 4.4 or 4.5. That pull request represents the effort toward "phase 1" of remote authentication requirements listed at
https://docs.google.com/document/d/1vcAmo2nkFYavAr7OwwXzxM0IFQbkRZYZrrX43q-wqGE/edit?usp=sharing . Once the pull request is merged we're running Shibboleth in production for a while at
https://dataverse.harvard.edu (which may require us registering as a Service Provider (SP) with InCommon first) we'll remove the "experimental" notice. We like to eat our own dog food. :)
I hope this helps. If you set up Drupal as a Shibboleth/SAML Identity Provider (IdP) and tell me where I can download your metadata, I'd be happy to add it to a test Dataverse server (after I send you its metadata, probably from
https://shibtest.dataverse.org which is my test server that you're welcome to play around with) so we can make sure login via your Drupal IdP solution works. Or you're welcome to do your own testing on a Dataverse server you install yourself, of course. :)
Shibboleth and SAML are very common in the academic community, but this is not what you had in mind for Single Sign On, please let me know! There's newer stuff like OAuth plus OpenID Connect (used by Google, Facebook, Twitter, et al.) but we've been focusing on Shibboleth and SAML for the phase 1 effort due to its popularity in higher education. The other thread where I've been posting Shibboleth updates is
https://groups.google.com/forum/#!topic/dataverse-community/pTmHCBVRE3oI hope this helps,
Phil