Google has just announced that Nexus 7 and Nexus 10 owners will wait no longer for their upgrade to Android 4.4, as the OTA update is starting today. To be clear, however, the new code is only rolling to WiFi-only 7-inch slates, so folks owning tablets with mobile data will have to wait. Naturally, we still have
no word on when the the rest of the Nexi (save the Galaxy Nexus, of course) will be getting KitKat, but at least some folks are getting the newest version of Android.
Update: According to Google's post on Google+, the Nexus 4 and mobile data-equipped Nexus 7 models should get the update "soon."