I agree that Jin is possibly alive and that's what brings Sun back to the island. I think her common interest with Widmore is finding the island.
Remember, Penny's tracking station is like in Antarctica or something? Although, yes, it would be funny if it were at a hatch. *snort* Antarctica/polar bear...certainly could be a funny connection.
Michael Emerson (Ben) really deserves and Emmy for his performance this season. Matthew Fox has been pretty outstanding, also. He's able to make the his character's stoicism and anguish both quite believable with expression and body language alone.
-A Shamrocktastic SharTribe Creation!