I have a Play 2.0 app deployed on EC2 and I start the app with play start and it runs in the background, I can hit Ctrl-D and the process will cont
I would suggest that you prepare the project deployment binary by using the stage command that the activator (formerly play) script takes. You can run that binary in the background, it can be found in the path which the second command in the code below shows.
./activator stage
target/universal/stage/bin/project-name &