General Motors have given a presentation at the ARC World Industry Forum about their new MES/automation link, which they have based on OPC UA. The automation link is done mainly with Kepware but on the MES side they are using Prosys OPC UA Java SDK. Go ahead and click the picture to view the complete video (in YouTube).

John Cooke explaining the architecture of the OPC UA based communication system. (Click to view the video)

The results are also pretty impressive (at 10:13 on the video):

Results of the GM MES integration upgrade.