When Google announced the Nexus 5 and Android 4.4 KitKat, one of the “new” apps that was launched was a new phone dialer that came with some unique features. The dialer came with an updated UI, featured Internet-based caller ID, and perhaps most notably, the ability to search for businesses and contacts, both on the device and from the Internet, from within the dialer. For now, it looks like Google is limiting the availability of this new dialer to Nexus devices and Google Play Edition smartphones. If you really want to get a copy of the dialer, it is now available if you meet a couple minimum requirements including root and an Android 4.4 ROM, either official or custom.
The dialer is available as both a flashable ZIP file to be installed via a custom recovery or as an APK file that is placed in /system/priv-app. For the latter option, you will need to be able to change the permissions of the APK file. Some users who have tried the install have reported the app icon does not show up in the app tray. It appears the solution to this problem is to use Nova Launcher and its feature that allows you to run a specific activity within an app. It also appears the default dialer needs to remain active in order for users to receive calls, but this could vary by device.
If you want to give the dialer a try, hit the source link to get the files and detailed install instructions.