Never heard of it. On something like a Jeep Liberty, you'd need to essentially rebuild the entire rear half of the vehicle.
The hack in question only applies to newer vehicles, and there is already a software update that can be applied by the dealer to resolve the issue. This won't fix the underlying problem of critical vehicle systems being connected to a cellular communication package (a profoundly stupid idea on the part of automakers, IMO), but welcome to the future I guess.
It's going to take a few high profile incidents before manufacturers really address this problem, unfortunately. After all, the security researchers in question did this public demonstration for a journalist precisely because Chrysler wasn't listening to them when they said the system was insecure.