Google provides an API to provision and authenticate users http://code.google.com/apis/apps/gdata_provisioning_api_v2.0_reference.html. It would be nice if Splunk could use google apps for your domain as an authentication source (alternatively using the SSO http://code.google.com/apis/apps/sso/saml_reference_implementation.html, or OpenID implementation http://code.google.com/apis/apps/sso/openid_reference_implementation.html).
A python example for Django is available at http://techblog.appirio.com/2008/10/google-apps-auth-backend-for-django.html
Are there any plans to support more authentication back ends any time soon, or is there a straightforward way that a new kind of authentication backend can be added?