As the title says, I'm interested in two (or more) simultaneous keyboards, each with a unique layout.

Everything I've researched indicates this should be possible, but I'm unable to get it to work. Regardless of how I set things up, all keyboards consistently operate as if they share the CoreDevice setting in xorg.conf. For example:

Code:
Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0" 0 0
    InputDevice    "Mouse0" "CorePointer"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Keyboard1"
    Option         "Xinerama" "0"
EndSection

Section "InputDevice"
    Identifier     "Keyboard0"
    Driver         "evdev"
    Option         "CoreKeyboard"
    Option         "Device" "/dev/input/event3"
    Option         "XkbRules" "xorg"
    Option         "XkbModel" "pc104"
    Option         "XkbLayout" "us"
EndSection

Section "InputDevice"
    Identifier     "Keyboard1"
    Driver         "evdev"
    Option         "Device" "/dev/input/event4"
    Option         "XkbRules" "xorg"
    Option         "XkbModel" "pc104"
    Option         "XkbLayout" "ad"
EndSection
In the above config, both keyboards behave as if they're set for the USA layout. Changing the layout in gnome-keyboard-properties affects all of the connected keyboards equally, but has no provision for altering individual devices.

Any suggestions?