So here's a quick explanation of how to sync down your own source for the android build (for right now it's CM9 and AOKP specific):
To start you will need to determine which code base you want to build for: CM9 or AOKP.
And then find that branch in the following project:
The default branch is "ics" and this should work for building both AOSP and CM9 (AOSP untested as of yet). If you want to build AOKP change the branch to "ics-aokp".
The README.mkdn contains the setup instructions for how to get started.
Once you've followed those instructions you can execute the following from the command line:
At the end of the long compile you can find your flashable ROM in the out/target/product/otter directory.
AS ALWAYS THE NEW KERNEL IS IN DEVELOPMENT. PLEASE WATCH YOUR BATTERY AND POWER OFF THE DEVICE WHEN NOT IN USE.