We received tips from a number of folks this morning that the Nexus 4 has finally had its source code dropped into AOSP - and it has! Sort of. If you head over to the Android Git, and to the /lge/mako repo, you'll notice lots of things that people with beards understand. And those things are, basically, the source code for the Nexus 4 (which is still called mako in AOSP, apparently).
As you already know, the Nexus 4's source code was not included on the day Android 4.2 was pushed into AOSP, with Android maintainer JBQ saying only that support for the Nexus 4 was not available "at the moment." Today, it seems that we're moving toward that goal - though we aren't there just yet.
Driver binaries for the Nexus 4 still haven't been published, and are a key ingredient for making a device usable with AOSP code. You won't get too far without them. However, said drivers can be ripped off existing Nexus 4's and, combined with the published code, should prove to make a workable solution for the time being if you're absolutely chomping at the bit to get knee-deep in that AOSP goodness.
Thanks to everyone who sent this in!