The 2.4L version of the engine had been sold in the Liberty in Europe and Australia since beginning of the Liberty, so I wouldn't exactly call it an "experiment". It was only a sales experiment in the US to see if they could sell a high powered, fuel efficient engine in a small bodied, medium weight SUV. Sounds hard...
I read somewhere that DC sold around twice as many CRD's as they first expected. I would say that was a successful experiment. The 2.8L CRD did not meet 2007 emissions standards in California and other states using the Cali emissions standards. With the basic design of the engine being more than 5 years old and the reduced sulphur deisel fuel supposed to be hitting the market in 2007-2008, it's probably a good time to break production and redesign the engine.
I did see some tv commercials (yes, I managed to stay awake and pay attention for all 30 seconds of those stupid DC commercials) over the summer that mentioned development of new, fuel efficient, reduced emissions deisels for 2008 model vehicles. No mention of specific models.