-The source code for 4.2 is being pushed to AOSP right now. Look for
it under the name "android-4.2_r1" once the replication completes. The
matching development branch (for CTS contributions) is jb-mr1-dev, and
all the changes are merged into the master branch where platform
contributions are accepted.
-Nexus 10 is now the best choice for AOSP work on 4.2. Everything
except the GPU code is Open Source, and the only proprietary binaries
besides the GPU libraries are firmware files that get loaded into the
various peripheral chips. No flagship device so far has been so open,
and no flagship device so far has had that level of AOSP support at
-Nexus 7 3G isn't supported. We haven't been able to license the GSM
stack for AOSP yet, and without the GSM stack this device doesn't do
more than a plain Nexus 7.
-If AOSP starts pointing toward Nexus 4, you are having a bad problem,
and you will not go to space today (i.e.: there is nothing in AOSP
related to Nexus 4).