The idea of Mozilla Persona is pretty interesting. Since YunoHost makes it easy for people to run their own email servers, operating as an identity provider for the Persona system would be a nice complement. I see that there is already an OpenID YunoHost app. Has anyone thought about making a Persona app?
I have not heard anything about a Persona app yet, but it would definitely worth the packaging 
That’s a good idea but not so simple 
Interesting reads on the subject:
Plugins and libraries in various langages
Bridge persona <-> LDAP
Persona for Apache
Lemon LDAP (a SSO based on ldap but for apache) can use it
http://lemonldap-ng.org/documentation/latest/authbrowserid
Moreover it seems that mozilla have somewhat abandoned persona… http://www.computerworld.com/article/2488440/search/mozilla-stops-work-on-persona-sign-on-to-shift-resources-to-firefox-os-services.html (1 year old article)