Take this how you will since we know messaging can be a bit different from service center to service center, but when I was in Arizona over New Year's and helped my injured Model S-owning cousin take his Feb. 2013 car in for service (regular service, but it's also got the drive unit milling noise), the Scottsdale service team told us that they COULD put a new DU in the car, but it would likely start doing the same thing after around 20k miles. They instead put my cousin on a list for when a new, totally redesigned DU would arrive at the service center after Fremont finishes it. He didn't give exact dates, citing that Fremont was busy getting the X out the door, but thought it would be early in the New Year.
Anyone heard anything similar?