This sounds like the kind of situation i had with crumpy's SRT. went down i October and they promised a new ECU by the end of January.
Best advice i can give you is to maintain contact with the dealer. check in with the parts guys. They know more than the service manager will tell you.
Be patient and polite, but persistant.
Chrysler is having issues with getting stuff from Diamler and what's left of Kharman. It is not the dealer so much as corporate. The dealer has a vested interest in you, not the corporate, so make friends with the parts guy.

I could not believe the difference in how they approaced my problem when I stopped bugging the Service manager and just talked nice to the parts guys.

maybe it'll work for you.

Good luck.

franc