From what I can gather from the github issue that was linked to, those would still require the email identity to be vouched for by a provider. (Though if whoever already is hosting my email could be a "provider", that would at least greatly expand the list of providers from the current small number of forges.) There doesn't seem to be any way for me to, for example, link a public key I generate myself to an email address that PyPI already has on file for me.