Send Jordan Zimmerman to the Sox for Ellsbury and Beckett? I am thinking the Sox could pull a prospect or two as well, but I don't know. The Nats are looking to shore up their CF of the future, and Ellsbury would give them a huge boost right now as well as give them a year to get him signed. Beckett would replace Zimmerman in the rotation, and Washington can afford his contract.
A move like this could push the Nats to the top of the favorites list in the NL right now, and keep them strong in the future. The Sox clearly aren't going to sign Ellsbury, and it is pretty clear Beckett's time in Boston is done. Zimmerman would be a good top of the rotation starter coming into his prime. I am not sure of his contract status, but I am assuming he is under control for a couple years.