Can locales be used to switch layouts? In my particular case I need to be able to switch the layout that the template extends. Is this possible to do using locales?
Untested, but should be fairly straightforward.

{% if craft.locale == 'de' %}
    {% set template = '_layout_de.html' %}
{% else %}
    {% set template = '_layout.html' %}
{% endif %}
{% extends template %}


or

{% extends craft.locale == 'de' ? '_layout_de.html' : '_layout.html' %}


or using a locale folder (thank josh baker)

{% extends craft.locale ~ '/_layout' %}