I may try to hack this in myself, but I really like the idea of JanRain's new OpenID selector, though having to load it from a remote site is less than ideal. I don't think it's a great thing for the comment website field, because it opens the second you click on the field. But adding it to the WP login screen's OpenID login field from the WP-OpenID plugin would be really nice.
I figure having a 3rd option 'Add ID Selector to login form' and a textarea to paste your custom ID Selector JS section would be all you needed. Will post a patch if I get the time to add it in.