Nexus S & Motorola Xoom not getting Android 4.2 JB, to remain on Android 4.1.2
Though Motorola Xoom is not Nexus branded, it is now owned by Google as the search engine giant bought Motorola and was thus provided with the Android 4.1 upgrade making it the first tablet to receive the upgrade.
There is no support for 4.2 on Nexus S and Xoom. Those devices should continue using 4.1.2. I can’t comment about the future of Nexus S and Xoom, sorry.