Pat has a very nice screenshot movie of the YADIS/XRI support he added to his SAML SSO PHP library.
Pat uses the OpenID favicon in the URL/XRI prompt.
I think this is perfectly appropriate as the ceremony he provides is exactly the same were the protocol OpenID and not SAML. Put another way, it's in the XRDS doc that the fact that the IDP speaks SAML and not OpenID is advertised, and not in the UI.
I do wonder though if an anarchist might resent having the "Big Business Driven" SAML (even ignoring the fundamental contribution of higher education) serve as the underlying protocol supporting their identity transactions?