Ross,
With JFBConnect, what you're looking for is possible. With JLinked, that's not possible yet. Until just recently, LinkedIn didn't allow us to import the user's email address. When they added the feature, we released v1.3 of JLinked which allows adds the email import feature, but we didn't have the time to add the automatic account creation ability in time for that release.
The upcoming v2.0 will add automatic account creation. That release is expected out later this year.
Hope that all helps explain, but if you have any other questions, just let us know!
Thanks,
Alex