Using OpenID login style instead of a seperated block
First! Thanks for this neat project.
Why don't you use a OpenID like approach for loging in instead of creating a new block.
This would allow developers to have the "regular" login block with a line/button with for OpenID and another line/button for Facebook.
It is a bad Usability approach to seperate as a different function what as an equal function.
See the following modules for inspiration on this one: http://drupal.org/project/comfortid
These are also neat links not totaly related: http://drupal.org/node/351066
Just my €0,02