Prince will cost you Cain so that pretty much is off the table. I do believe that Beltre is high on their list and probably more attainable without giving the two linchpins. You would probably have to give up Sanchez, especially if Lowry recovers but it seems lopsided in the favor of Seattle.

That being said, Beltre would be an ideal fit with him playing third and a power hitter that the Giants desperately need.

If you stick Beltre in the fourth spot, I think the rest of the lineup kinda balances itself out.

2009 Lineup:

Winn
Lewis
Sandoval
Beltre
Molina
Rowand
Frandsen
Burris