The factory images for the new Nexus 7 (razorg) Android 4.3 (JLS36C) are out!
Official download link images(razorg): https://developers.google.com/android/nexus/images#razorg
… and binaries(deb): https://developers.google.com/android/nexus/drivers#razorg
Another download option + insecure boot image and deodexed system is here:
http://web.djodjo.org/article/download/android/ROM_images/factory_images_gn_razorg