Download updated KitKat 4.4 apps here! (UPDATE 3: Added Calculator, Maps, Play Books, QuickOffice, Street View, and Play Games)
Clock app (courtesy of Android Police), link here
Hangouts app (courtesy of Luke Olsen), link here
Google Play Launcher, Google Now, Google Play Services (courtesy of Phandroid), (EDIT: Download at your own risk, Google Now force closes on my Nexus 4 when trying to search and when trying to change wallpapers, otherwise everything else is fine), link here
Calendar, Email (not Gmail), Gallery, Gmail, Camera, Keep, Keyboard, Wallpapers, and everything else from above (courtesy of Droid Life), link here
Calculator, Maps, Play Books and Games, QuickOffice, Street View, (courtesy of Phandroid), link here
Also for those who care, here's a link to the Nexus 5 4.4 stock ROM image.
This forum post will be updated as I learn of new info about updated apps. Anyone who knows anything, feel free to contribute down below.