Has that ever happened?
I'm unaware of anyone ever being released from Federal prison in a prisoner exchange.
Also, if al Qaeda really wanted him, wouldn't they have tried to get him back in the last 1700 or so days since he was arrested?
I don't think al Qaeda cares about him one pico-iotta. Remember the tape of bin Laden [link|http://observer.guardian.co.uk/international/story/0,6903,619480,00.html|laughing] about his guys on the planes?
Life in prison is probably the best punishment for him, IMHO.
Cheers,
Scott.