As far as I can see, there is no way. It doesn’t look like the signup is stored in the database before the user clicks on the verification link. The verification link most likely contains all the information for signup in the URL parameter.
One one hand I like that: The users information isn’t stored until it is really confirmed. But it also doesn’t give you a feeling about the number of non-verified users. And as the signup process doesn’t seem to work flawlessly (yet), that would be a good indicator to have.