[OpenID] An OpenID "mobile" Hint?

[David Recordon]

In developing a mobile application that uses OpenID for logins one of  
the things I've become really cognizant of is how poor of the mobile  
experience most Providers have when it comes to OpenID.  It obviously  
doesn't take a lot to create a streamlined Provider flow for  
authentication and the trust request, but so far it seems that no one  
has really done that.  I was also thinking more about Providers such  
as YubiKey where authenticating with a USB device (despite how awesome  
it is) won't work on my iPhone.

I'm wondering if it would be useful to write a dead simple extension  
to provide some hints around mobile support?  Allow a Provider to  
advertise in an XRDS file that they support a mobile login flow so  
that Relying Parties could discover that theoretically making it so  
that I could use a Provider such as YubiKey on the desktop and then  
MyOpenID on the phone.

Am I barking up a useful tree?  If I spec'd this would any Providers  
actually implement a mobile friendly flow?

--David