After an early tease with the Nexus Player, it looks like Android 5.1.1 is legitimately rolling out to the Nexus family. An OTA for the Nexus 10 was spotted just a few hours ago, and now factory images and binaries have been posted for that tablet and both generations of the Nexus 7 (Wi-Fi only, for now). There haven't been any OTA reports for the two smaller tablets, but they will probably start rolling out shortly.
There are still no signs of OTAs or factory images for the seemingly ignored Nexus 9, nor any phone or tablet with a cellular radio. However, now that the traditional devices are on the right track, the rest should catch up shortly. We'll keep an eye out for additional updates and post about them as they appear.
If you can't wait to move up to the very latest version, we've got instructions here for flashing factory images to your Nexus devices.