Thanks to an unfortunate injury, you can add another name to the potential DH list in 2011: Magglio Ordonez. Ordonez, with the injury, won't collect the necessary at bats to make his 2011 vesting option. While Ordonez could very well resign with Detroit to a reduced salary for next year, it adds another potential option for the Rays.
If the Rays don't resign Pena, or are looking to fill the DH void, there could be guys like Ordonez, David Ortiz, Jason Kubel, Lance Berkman, Russel Branyan, Adam LaRoche, Paul Konerko, etc. available. The point is, the Rays have options potentially on the cheap to retool this area of need next year. If anything, it might make Pena's contract demands reasonable enough to warrant resigning him.