Yes, GDE (Green Diesel Engineering) makes a tuner for the Ecodiesel.
EDIT: makes a "tune" or program, not a tuner.
I just spent some time reading up about it and am now a bit confused.
Apparently they manipulate the turbo to increase "engine" braking, but it's not really an "exhaust" brake. Some people call it a "turbo" brake, GDE calls it an "engine" brake. Don't understand the difference really.
Apparently the GDE brake is not as strong as a true "exhaust" brake.
But as I'm told stock diesels have very poor "engine" braking by themselves, GDE's "turbo" brake seems like an excellent idea.
By all accounts the GDE "turbo" brake is well integrated with the transmission's downshift braking.