This has been bothering me real bad. Ever since installing Mavericks, the default login keyboard at the Apple login screen seems to be the standard US (QWERTY). Since I live in the AZERTY world, this ain't no good at all. For the months I been using Mavericks, this proved a real pain in the b*%+/. Unfortunately, I been rather lazy to go find out how to fix the issue. Solutions from 'misery loves company' alike fora weren't actually forthcoming either... On the long run, I even got used fooling OSX, typing on an AZERTY keyboard, and pretending it was on QWERTY; it ain't such a smart feat, however. Problem is, when you just happen to login early in the morning, you're kind of brain-dead... mostly turns out that you don't wanna make your brain work yet, and it's a nuisance to realize, after a few 'wrong password' pop-ups, that you been typing on a different keyboard that the computer thought you oughtta be using.
In the beginning I kinda 'helped' the problem by following these instructions by Apple itself. They make a default login keyboard menu item appear at the right-up corner of the toolbar at the top of the monitor. However, this seems to always be the US standard, regardless whether, after booting, keyboards will revert to the versions users specify in their Preferences 'Language and Region' panes. With Apple's solution, you needed to select first the correct keyboard from the drop-down and then to login. Worth noticing, there's no other predefined keyboards than the US at this login screen, so you need to seek yours inside an ethnic list of keyboards first, and then select it to type your credentials and login. Quite a fuss if you ask me... Gotta be a better way than that...
Indeed and Eureka! A far more elegant solution does exist. To understand what's goin' on, figure this. OSX stores the default login keyboard in the root Library Preferences, however, there are two types of Libraries: one is the mentioned root, which is also visible, and a second is the user Library, invisible ever since Mavericks, and it was created inside the user folders. After you, as a user, select several working keyboards, the list is written into your user's Library, and not in the root Library. It's in the preferences of that root Library that the US standard keyboard is glued down and won't go away. Unless... you copy your user keyboard preferences from the user into the root Library.
To do that, simply open Terminal and copy this:
sudo cp ~/Library/Preferences/com.apple.HIToolbox.plist /Library/Preferences/
You do that, then enter your password, and all's said and done. Logoff and login again. At your keyboard drop-down you'll now find all the keyboards that you specified in your 'Language and Region' panes.