We don't have definite plans to build a full-featured IDP, but we did build a Mock IDP we use in CI, QA and demos that could possibly be a starting point for your purposes? Other OSS IDPs include Keycloak and Gluu Server if you wanted to check those out!
https://github.com/enterprise-oss/sinatra-ruby-idp https://www.keycloak.org/ https://www.gluu.org/