It appears that all Flickr user pages are now OpenIDs. They identify https://open.login.yahooapis.com/openid/op/auth as the OpenID endpoint. I don’t have a Flickr account, so I can’t try it out …
Chalk up another so many millions of OpenIDs in the market … (Anybody know how many users Flickr has these days? Somebody called Todd claims here on ReadWriteWeb that it is 28 million)