Mine would be:
1. Middle of the order right handed power/average bat.
2. A #1 or #2 type starter.
I think they'd have to trade Stubbs, Alonso, and one or two of the young pitchers to get this done. Maybe even Grandal. And Stubbs, Alonso, and Grandal are all former #1 picks, so that should count for something.
My triple A prospects/major league young player untouchables are Mez and Francisco. I think Juan is ready to take flight and Rolen has one year left on his contract.
The problem is going to be getting Dusty to platoon Francisco/Rolen at 3B.