It’s not going to happen, because if Hamas cuts a deal to release Shalit, even if it gets a truce and (somewhat more) open borders, it cuts its own throat.
Because Hamas’ credibility comes in large part from its absolutist positions,* a negotiation which results in Shalit’s release would be seen by many of their supporters as a capitulation and a defeat, and this would compromise their political viability, both in Gaza and in the West Bank.
The short form is that if Hamas did this, they would be signing their own death warrant.
*I was going to use the “takes no prisoners” metaphor, but given the situation here, it just doesn’t work.