In the ongoing "world" of IdP discovery a new proposal has been made by Brad Fitzpatrick on his blog. This proposal provides for a direct mapping between an email address and a personal URL (e.g. an OpenID). The mapping between the email address and personal URL is provided by an email2url_mapping service run by the email provider. Discovery of the email2url_mapping service endpoint is found via XRI URL resolution on the domain of the email address.
Whether the user needs the full indirection capability to have an arbitrary mapping between email address and URL or is fine with allowing the email provider to be their OP/IdP is yet to be seen. It is encouraging to see consumer's UX needs being addressed.