What I'd like to know is if I can use Facebook Connect to port my graph over (doubt Facebook would allow this) -- or if this means starting from scratch yet again.
[1]: http://tech.slashdot.org/story/10/10/07/1250242/Facebook-Imp...
I don't know exactly what's the file format from FB backup, but it might be possible to identify linked users based on similar content (as long as both users have already uploaded their profile to Google+).