Google has released an early Christmas present for Android users, with Android 5.0.1 factory images for the Nexus 9, Nexus 7, and Nexus 10 last week. Now the Nexus 6 and Nexus 4 smartphones can enjoy those same images.
You can grab the Nexus 6 Android 5.0.1 factory image here, while the Nexus 4 Android 5.0.1 factory image can be obtained here. Android Central has a great guide on manually updating your Nexus device before you use these factory images, something we definitely recommend. It shouldn't be long until Google pushes these updates over-the-air (OTA) but until then, you've got some factory images to play with.